20851257544 has 32 divisors (see below), whose sum is σ = 42110523000. Its totient is φ = 9622052352.

The previous prime is 20851257527. The next prime is 20851257563. The reversal of 20851257544 is 44575215802.

It can be written as a sum of positive squares in 4 ways, for example, as 17354900644 + 3496356900 = 131738^2 + 59130^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 20851257544.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 801412 + ... + 827020.

Almost surely, 2^20851257544 is an apocalyptic number.

It is an amenable number.

20851257544 is an abundant number, since it is smaller than the sum of its proper divisors (21259265456).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20851257544 is a wasteful number, since it uses less digits than its factorization.

20851257544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33457 (or 33453 counting only the distinct ones).

The product of its (nonzero) digits is 448000, while the sum is 43.

The spelling of 20851257544 in words is "twenty billion, eight hundred fifty-one million, two hundred fifty-seven thousand, five hundred forty-four".