21324831 has 16 divisors (see below), whose sum is σ = 32088960. Its totient is φ = 12477920.

The previous prime is 21324803. The next prime is 21324847. The reversal of 21324831 is 13842312.

It is a cyclic number.

It is not a de Polignac number, because 21324831 - 2¹³ = 21316639 is a prime.

It is a super-2 number, since 2×21324831² = 909496834357122, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21324871) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10185 + ... + 12098.

It is an arithmetic number, because the mean of its divisors is an integer number (2005560).

Almost surely, 2^21324831 is an apocalyptic number.

21324831 is a deficient number, since it is larger than the sum of its proper divisors (10764129).

21324831 is a wasteful number, since it uses less digits than its factorization.

21324831 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22326.

The product of its digits is 1152, while the sum is 24.

The square root of 21324831 is about 4617.8816572104. The cubic root of 21324831 is about 277.3076599151.

It can be divided in two parts, 21324 and 831, that added together give a triangular number (22155 = T₂₁₀).

The spelling of 21324831 in words is "twenty-one million, three hundred twenty-four thousand, eight hundred thirty-one".