21555132025 has 12 divisors (see below), whose sum is σ = 30546701632. Its totient is φ = 14780661840.

The previous prime is 21555131999. The next prime is 21555132029. The reversal of 21555132025 is 52023155512.

It is not a de Polignac number, because 21555132025 - 2²¹ = 21553034873 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21555132029) 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, 61585917 + ... + 61586266.

Almost surely, 2^21555132025 is an apocalyptic number.

21555132025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21555132025 is a deficient number, since it is larger than the sum of its proper divisors (8991569607).

21555132025 is a wasteful number, since it uses less digits than its factorization.

21555132025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123172200 (or 123172195 counting only the distinct ones).

The product of its (nonzero) digits is 15000, while the sum is 31.

Adding to 21555132025 its reverse (52023155512), we get a palindrome (73578287537).

The spelling of 21555132025 in words is "twenty-one billion, five hundred fifty-five million, one hundred thirty-two thousand, twenty-five".