21257777898 has 72 divisors (see below), whose sum is σ = 54223985088. Its totient is φ = 6000453648.

The previous prime is 21257777881. The next prime is 21257777903. The reversal of 21257777898 is 89877775212.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 71986 + ... + 218397.

It is an arithmetic number, because the mean of its divisors is an integer number (753110904).

Almost surely, 2^21257777898 is an apocalyptic number.

21257777898 is an abundant number, since it is smaller than the sum of its proper divisors (32966207190).

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

21257777898 is a wasteful number, since it uses less digits than its factorization.

21257777898 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 290488 (or 290478 counting only the distinct ones).

The product of its digits is 27659520, while the sum is 63.

The spelling of 21257777898 in words is "twenty-one billion, two hundred fifty-seven million, seven hundred seventy-seven thousand, eight hundred ninety-eight".