21019272 has 16 divisors (see below), whose sum is σ = 52548240. Its totient is φ = 7006416.

The previous prime is 21019261. The next prime is 21019277. The reversal of 21019272 is 27291012.

It is a Harshad number since it is a multiple of its sum of digits (24), and also a Moran number because the ratio is a prime number: 875803 = 21019272 / (2 + 1 + 0 + 1 + 9 + 2 + 7 + 2).

It is not an unprimeable number, because it can be changed into a prime (21019277) 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, 437878 + ... + 437925.

It is an arithmetic number, because the mean of its divisors is an integer number (3284265).

Almost surely, 2^21019272 is an apocalyptic number.

It is an amenable number.

21019272 is an abundant number, since it is smaller than the sum of its proper divisors (31528968).

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

21019272 is a wasteful number, since it uses less digits than its factorization.

21019272 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 875812 (or 875808 counting only the distinct ones).

The product of its (nonzero) digits is 504, while the sum is 24.

The square root of 21019272 is about 4584.6779603370. The cubic root of 21019272 is about 275.9767886382.

The spelling of 21019272 in words is "twenty-one million, nineteen thousand, two hundred seventy-two".