21547212 has 12 divisors (see below), whose sum is σ = 50276856. Its totient is φ = 7182400.

The previous prime is 21547199. The next prime is 21547217. The reversal of 21547212 is 21274512.

It is a tau number, because it is divible by the number of its divisors (12).

It is not an unprimeable number, because it can be changed into a prime (21547217) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 897789 + ... + 897812.

It is an arithmetic number, because the mean of its divisors is an integer number (4189738).

Almost surely, 2^21547212 is an apocalyptic number.

It is an amenable number.

21547212 is an abundant number, since it is smaller than the sum of its proper divisors (28729644).

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

21547212 is a wasteful number, since it uses less digits than its factorization.

21547212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1795608 (or 1795606 counting only the distinct ones).

The product of its digits is 1120, while the sum is 24.

The square root of 21547212 is about 4641.8974568596. The cubic root of 21547212 is about 278.2682744024.

It can be divided in two parts, 215472 and 12, that multiplied together give a square (2585664 = 1608²).

The spelling of 21547212 in words is "twenty-one million, five hundred forty-seven thousand, two hundred twelve".