21450625 has 20 divisors (see below), whose sum is σ = 30640192. Its totient is φ = 14706000.

The previous prime is 21450623. The next prime is 21450629. The reversal of 21450625 is 52605412.

It is not a de Polignac number, because 21450625 - 2¹ = 21450623 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21450625.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21450623) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 1924 + ... + 6826.

Almost surely, 2^21450625 is an apocalyptic number.

21450625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21450625 is a deficient number, since it is larger than the sum of its proper divisors (9189567).

21450625 is an frugal number, since it uses more digits than its factorization.

21450625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4930 (or 4915 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 25.

The square root of 21450625 is about 4631.4819442593. The cubic root of 21450625 is about 277.8518654231.

The spelling of 21450625 in words is "twenty-one million, four hundred fifty thousand, six hundred twenty-five".