21372612 has 48 divisors (see below), whose sum is σ = 52426752. Its totient is φ = 6763680.

The previous prime is 21372577. The next prime is 21372629. The reversal of 21372612 is 21627312.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 58053 + ... + 58419.

It is an arithmetic number, because the mean of its divisors is an integer number (1092224).

Almost surely, 2^21372612 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21372612, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26213376).

21372612 is an abundant number, since it is smaller than the sum of its proper divisors (31054140).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21372612 is a wasteful number, since it uses less digits than its factorization.

21372612 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 608 (or 606 counting only the distinct ones).

The product of its digits is 1008, while the sum is 24.

The square root of 21372612 is about 4623.0522385108. The cubic root of 21372612 is about 277.5146197963.

Adding to 21372612 its reverse (21627312), we get a palindrome (42999924).

The spelling of 21372612 in words is "twenty-one million, three hundred seventy-two thousand, six hundred twelve".