21418925 has 24 divisors (see below), whose sum is σ = 29408832. Its totient is φ = 15344000.

The previous prime is 21418889. The next prime is 21418937. The reversal of 21418925 is 52981412.

It is not a de Polignac number, because 21418925 - 2²⁴ = 4641709 is a prime.

It is a hoax number, since the sum of its digits (32) coincides with the sum of the digits of its distinct prime factors.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21418891 and 21418900.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 18977 + ... + 20073.

It is an arithmetic number, because the mean of its divisors is an integer number (1225368).

Almost surely, 2^21418925 is an apocalyptic number.

21418925 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21418925 is a deficient number, since it is larger than the sum of its proper divisors (7989907).

21418925 is a wasteful number, since it uses less digits than its factorization.

21418925 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1189 (or 1184 counting only the distinct ones).

The product of its digits is 5760, while the sum is 32.

The square root of 21418925 is about 4628.0584482048. The cubic root of 21418925 is about 277.7149269654.

The spelling of 21418925 in words is "twenty-one million, four hundred eighteen thousand, nine hundred twenty-five".