21628751825 has 12 divisors (see below), whose sum is σ = 26821580928. Its totient is φ = 17301757200.

The previous prime is 21628751773. The next prime is 21628751843. The reversal of 21628751825 is 52815782612.

It is a de Polignac number, because none of the positive numbers 2^k-21628751825 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21628751825.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 503960 + ... + 545190.

It is an arithmetic number, because the mean of its divisors is an integer number (2235131744).

Almost surely, 2^21628751825 is an apocalyptic number.

21628751825 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21628751825 is a deficient number, since it is larger than the sum of its proper divisors (5192829103).

21628751825 is a wasteful number, since it uses less digits than its factorization.

21628751825 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62224 (or 62219 counting only the distinct ones).

The product of its digits is 537600, while the sum is 47.

The spelling of 21628751825 in words is "twenty-one billion, six hundred twenty-eight million, seven hundred fifty-one thousand, eight hundred twenty-five".