20699044657 has 4 divisors (see below), whose sum is σ = 21788468080. Its totient is φ = 19609621236.

The previous prime is 20699044631. The next prime is 20699044673. The reversal of 20699044657 is 75644099602.

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 20699044657 - 2²⁷ = 20564826929 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20699044607) 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, 544711683 + ... + 544711720.

It is an arithmetic number, because the mean of its divisors is an integer number (5447117020).

Almost surely, 2^20699044657 is an apocalyptic number.

It is an amenable number.

20699044657 is a deficient number, since it is larger than the sum of its proper divisors (1089423423).

20699044657 is a wasteful number, since it uses less digits than its factorization.

20699044657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1089423422.

The product of its (nonzero) digits is 3265920, while the sum is 52.

Subtracting 20699044657 from its reverse (75644099602), we obtain a palindrome (54945054945).

The spelling of 20699044657 in words is "twenty billion, six hundred ninety-nine million, forty-four thousand, six hundred fifty-seven".