21164621025 has 12 divisors (see below), whose sum is σ = 34992173552. Its totient is φ = 11287797840.

The previous prime is 21164621021. The next prime is 21164621047. The reversal of 21164621025 is 52012646112.

It is not a de Polignac number, because 21164621025 - 2² = 21164621021 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21164620983 and 21164621001.

It is not an unprimeable number, because it can be changed into a prime (21164621021) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 141097399 + ... + 141097548.

Almost surely, 2^21164621025 is an apocalyptic number.

21164621025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21164621025 is a deficient number, since it is larger than the sum of its proper divisors (13827552527).

21164621025 is a wasteful number, since it uses less digits than its factorization.

21164621025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 282194960 (or 282194955 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 30.

The spelling of 21164621025 in words is "twenty-one billion, one hundred sixty-four million, six hundred twenty-one thousand, twenty-five".