21613372 has 12 divisors (see below), whose sum is σ = 41261976. Its totient is φ = 9824240.

The previous prime is 21613367. The next prime is 21613379. The reversal of 21613372 is 27331612.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21613379) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 245563 + ... + 245650.

It is an arithmetic number, because the mean of its divisors is an integer number (3438498).

Almost surely, 2^21613372 is an apocalyptic number.

21613372 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21613372 is a deficient number, since it is larger than the sum of its proper divisors (19648604).

21613372 is a wasteful number, since it uses less digits than its factorization.

21613372 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 491228 (or 491226 counting only the distinct ones).

The product of its digits is 1512, while the sum is 25.

The square root of 21613372 is about 4649.0183910155. The cubic root of 21613372 is about 278.5527879077.

Adding to 21613372 its reverse (27331612), we get a palindrome (48944984).

The spelling of 21613372 in words is "twenty-one million, six hundred thirteen thousand, three hundred seventy-two".