21297672 has 48 divisors (see below), whose sum is σ = 62927280. Its totient is φ = 6453600.

The previous prime is 21297667. The next prime is 21297673. The reversal of 21297672 is 27679212.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (21297673) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 12654 + ... + 14237.

It is an arithmetic number, because the mean of its divisors is an integer number (1310985).

Almost surely, 2^21297672 is an apocalyptic number.

21297672 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21297672 is an abundant number, since it is smaller than the sum of its proper divisors (41629608).

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

21297672 is a wasteful number, since it uses less digits than its factorization.

21297672 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26914 (or 26907 counting only the distinct ones).

The product of its digits is 21168, while the sum is 36.

The square root of 21297672 is about 4614.9400862850. The cubic root of 21297672 is about 277.1898848779.

It can be divided in two parts, 2129 and 7672, that added together give a square (9801 = 99²).

The spelling of 21297672 in words is "twenty-one million, two hundred ninety-seven thousand, six hundred seventy-two".