20561770397 has 8 divisors (see below), whose sum is σ = 23897457600. Its totient is φ = 17325656064.

The previous prime is 20561770373. The next prime is 20561770399. The reversal of 20561770397 is 79307716502.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20561770397 - 2¹⁴ = 20561754013 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20561770399) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24892772 + ... + 24893597.

It is an arithmetic number, because the mean of its divisors is an integer number (2987182200).

Almost surely, 2^20561770397 is an apocalyptic number.

It is an amenable number.

20561770397 is a deficient number, since it is larger than the sum of its proper divisors (3335687203).

20561770397 is an equidigital number, since it uses as much as digits as its factorization.

20561770397 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49786435.

The product of its (nonzero) digits is 555660, while the sum is 47.

The spelling of 20561770397 in words is "twenty billion, five hundred sixty-one million, seven hundred seventy thousand, three hundred ninety-seven".