21329172 has 36 divisors (see below), whose sum is σ = 56754880. Its totient is φ = 6735312.

The previous prime is 21329167. The next prime is 21329177. The reversal of 21329172 is 27192312.

It is an interprime number because it is at equal distance from previous prime (21329167) and next prime (21329177).

It is a tau number, because it is divible by the number of its divisors (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21329177) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 14908 + ... + 16275.

Almost surely, 2^21329172 is an apocalyptic number.

It is an amenable number.

21329172 is an abundant number, since it is smaller than the sum of its proper divisors (35425708).

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

21329172 is a wasteful number, since it uses less digits than its factorization.

21329172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31212 (or 31207 counting only the distinct ones).

The product of its digits is 1512, while the sum is 27.

The square root of 21329172 is about 4618.3516539995. The cubic root of 21329172 is about 277.3264753965.

The spelling of 21329172 in words is "twenty-one million, three hundred twenty-nine thousand, one hundred seventy-two".