21115351525 has 12 divisors (see below), whose sum is σ = 26300455552. Its totient is φ = 16816526640.

The previous prime is 21115351513. The next prime is 21115351571. The reversal of 21115351525 is 52515351112.

It is not a de Polignac number, because 21115351525 - 2⁹ = 21115351013 is a prime.

It is a Duffinian number.

It is a congruent number.

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, 1888179 + ... + 1899328.

Almost surely, 2^21115351525 is an apocalyptic number.

21115351525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21115351525 is a deficient number, since it is larger than the sum of its proper divisors (5185104027).

21115351525 is a wasteful number, since it uses less digits than its factorization.

21115351525 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3787740 (or 3787735 counting only the distinct ones).

The product of its digits is 7500, while the sum is 31.

The spelling of 21115351525 in words is "twenty-one billion, one hundred fifteen million, three hundred fifty-one thousand, five hundred twenty-five".