21451005625 has 80 divisors (see below), whose sum is σ = 31939776000. Its totient is φ = 14389536000.

The previous prime is 21451005623. The next prime is 21451005629. The reversal of 21451005625 is 52650015412.

It is not a de Polignac number, because 21451005625 - 2¹ = 21451005623 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21451005623) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 10074561 + ... + 10076689.

It is an arithmetic number, because the mean of its divisors is an integer number (399247200).

Almost surely, 2^21451005625 is an apocalyptic number.

21451005625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21451005625 is a deficient number, since it is larger than the sum of its proper divisors (10488770375).

21451005625 is an frugal number, since it uses more digits than its factorization.

21451005625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2217 (or 2188 counting only the distinct ones).

The product of its (nonzero) digits is 12000, while the sum is 31.

The spelling of 21451005625 in words is "twenty-one billion, four hundred fifty-one million, five thousand, six hundred twenty-five".