20499469637957 has 4 divisors (see below), whose sum is σ = 20516369449260. Its totient is φ = 20482569826656.

The previous prime is 20499469637893. The next prime is 20499469637963. The reversal of 20499469637957 is 75973696499402.

It is a Cunningham number, because it is equal to 4527634²+1.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 836284644196 + 19663184993761 = 914486^2 + 4434319^2 .

It is a cyclic number.

It is not a de Polignac number, because 20499469637957 - 2⁶ = 20499469637893 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 (20499469637987) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8449903832 + ... + 8449906257.

It is an arithmetic number, because the mean of its divisors is an integer number (5129092362315).

Almost surely, 2^{20499469637957} is an apocalyptic number.

It is an amenable number.

20499469637957 is a deficient number, since it is larger than the sum of its proper divisors (16899811303).

20499469637957 is a wasteful number, since it uses less digits than its factorization.

20499469637957 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16899811302.

The product of its (nonzero) digits is 5555329920, while the sum is 80.

The spelling of 20499469637957 in words is "twenty trillion, four hundred ninety-nine billion, four hundred sixty-nine million, six hundred thirty-seven thousand, nine hundred fifty-seven".