20309957457 has 4 divisors (see below), whose sum is σ = 27079943280. Its totient is φ = 13539971636.

The previous prime is 20309957449. The next prime is 20309957461. The reversal of 20309957457 is 75475990302.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20309957457 - 2³ = 20309957449 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20309917457) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3384992907 + ... + 3384992912.

It is an arithmetic number, because the mean of its divisors is an integer number (6769985820).

Almost surely, 2^20309957457 is an apocalyptic number.

It is an amenable number.

20309957457 is a deficient number, since it is larger than the sum of its proper divisors (6769985823).

20309957457 is an equidigital number, since it uses as much as digits as its factorization.

20309957457 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6769985822.

The product of its (nonzero) digits is 2381400, while the sum is 51.

The spelling of 20309957457 in words is "twenty billion, three hundred nine million, nine hundred fifty-seven thousand, four hundred fifty-seven".