21332731 has 8 divisors (see below), whose sum is σ = 24724224. Its totient is φ = 18027240.

The previous prime is 21332711. The next prime is 21332761. The reversal of 21332731 is 13723312.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21332731 - 2¹³ = 21324539 is a prime.

It is a super-2 number, since 2×21332731² = 910170823836722, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21332711) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20965 + ... + 21958.

It is an arithmetic number, because the mean of its divisors is an integer number (3090528).

Almost surely, 2^21332731 is an apocalyptic number.

21332731 is a deficient number, since it is larger than the sum of its proper divisors (3391493).

21332731 is an equidigital number, since it uses as much as digits as its factorization.

21332731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43001.

The product of its digits is 756, while the sum is 22.

The square root of 21332731 is about 4618.7369485607. The cubic root of 21332731 is about 277.3418994994.

The spelling of 21332731 in words is "twenty-one million, three hundred thirty-two thousand, seven hundred thirty-one".