20998937987457 has 16 divisors (see below), whose sum is σ = 29652235255872. Its totient is φ = 13172837230080.

The previous prime is 20998937987453. The next prime is 20998937987459. The reversal of 20998937987457 is 75478973989902.

It is a happy number.

It is not a de Polignac number, because 20998937987457 - 2² = 20998937987453 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20998937987453) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 46130623 + ... + 46583604.

It is an arithmetic number, because the mean of its divisors is an integer number (1853264703492).

Almost surely, 2^{20998937987457} is an apocalyptic number.

It is an amenable number.

20998937987457 is a deficient number, since it is larger than the sum of its proper divisors (8653297268415).

20998937987457 is a wasteful number, since it uses less digits than its factorization.

20998937987457 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 92718688.

The product of its (nonzero) digits is 17283248640, while the sum is 87.

The spelling of 20998937987457 in words is "twenty trillion, nine hundred ninety-eight billion, nine hundred thirty-seven million, nine hundred eighty-seven thousand, four hundred fifty-seven".