21219972 has 24 divisors (see below), whose sum is σ = 50254176. Its totient is φ = 6967488.

The previous prime is 21219949. The next prime is 21219977. The reversal of 21219972 is 27991212.

It is not an unprimeable number, because it can be changed into a prime (21219977) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12393 + ... + 14000.

It is an arithmetic number, because the mean of its divisors is an integer number (2093924).

Almost surely, 2^21219972 is an apocalyptic number.

It is an amenable number.

21219972 is an abundant number, since it is smaller than the sum of its proper divisors (29034204).

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

21219972 is a wasteful number, since it uses less digits than its factorization.

21219972 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26467 (or 26465 counting only the distinct ones).

The product of its digits is 4536, while the sum is 33.

The square root of 21219972 is about 4606.5140833389. The cubic root of 21219972 is about 276.8523847807.

The spelling of 21219972 in words is "twenty-one million, two hundred nineteen thousand, nine hundred seventy-two".