21547372 has 24 divisors (see below), whose sum is σ = 47013120. Its totient is φ = 8394960.

The previous prime is 21547369. The next prime is 21547391. The reversal of 21547372 is 27374512.

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 7 ways as a sum of consecutive naturals, for example, 34672 + ... + 35287.

It is an arithmetic number, because the mean of its divisors is an integer number (1958880).

Almost surely, 2^21547372 is an apocalyptic number.

21547372 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21547372 is an abundant number, since it is smaller than the sum of its proper divisors (25465748).

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

21547372 is a wasteful number, since it uses less digits than its factorization.

21547372 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69981 (or 69979 counting only the distinct ones).

The product of its digits is 11760, while the sum is 31.

The square root of 21547372 is about 4641.9146911592. The cubic root of 21547372 is about 278.2689631661.

The spelling of 21547372 in words is "twenty-one million, five hundred forty-seven thousand, three hundred seventy-two".