20757946975921 has 3 divisors (see below), whose sum is σ = 20757951532011. Its totient is φ = 20757942419832.

The previous prime is 20757946975919. The next prime is 20757946975943. The reversal of 20757946975921 is 12957964975702.

The square root of 20757946975921 is 4556089.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 20641474937521 + 116472038400 = 4543289^2 + 341280^2 .

It is not a de Polignac number, because 20757946975921 - 2¹ = 20757946975919 is a prime.

It is a super-3 number, since 3×20757946975921³ (a number of 41 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20757946975991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 2278045 + ... + 6834133.

It is an arithmetic number, because the mean of its divisors is an integer number (6919317177337).

Almost surely, 2^{20757946975921} is an apocalyptic number.

20757946975921 is the 4556089-th square number.

20757946975921 is the 2278045-th centered octagonal number.

It is an amenable number.

20757946975921 is a deficient number, since it is larger than the sum of its proper divisors (4556090).

20757946975921 is an frugal number, since it uses more digits than its factorization.

20757946975921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9112178 (or 4556089 counting only the distinct ones).

The product of its (nonzero) digits is 600112800, while the sum is 73.

The spelling of 20757946975921 in words is "twenty trillion, seven hundred fifty-seven billion, nine hundred forty-six million, nine hundred seventy-five thousand, nine hundred twenty-one".