21372025 has 6 divisors (see below), whose sum is σ = 26501342. Its totient is φ = 17097600.

The previous prime is 21372023. The next prime is 21372031. The reversal of 21372025 is 52027312.

It can be written as a sum of positive squares in 3 ways, for example, as 36864 + 21335161 = 192^2 + 4619^2 .

It is not a de Polignac number, because 21372025 - 2¹ = 21372023 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21371987 and 21372005.

It is not an unprimeable number, because it can be changed into a prime (21372023) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 427416 + ... + 427465.

Almost surely, 2^21372025 is an apocalyptic number.

21372025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21372025 is a deficient number, since it is larger than the sum of its proper divisors (5129317).

21372025 is an equidigital number, since it uses as much as digits as its factorization.

21372025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 854891 (or 854886 counting only the distinct ones).

The product of its (nonzero) digits is 840, while the sum is 22.

The square root of 21372025 is about 4622.9887518790. The cubic root of 21372025 is about 277.5120791214.

Adding to 21372025 its reverse (52027312), we get a palindrome (73399337).

The spelling of 21372025 in words is "twenty-one million, three hundred seventy-two thousand, twenty-five".