21164031 has 48 divisors (see below), whose sum is σ = 38659680. Its totient is φ = 11370240.

The previous prime is 21164029. The next prime is 21164047. The reversal of 21164031 is 13046112.

It is a happy number.

21164031 is a `hidden beast` number, since 21 + 1 + 640 + 3 + 1 = 666.

It is not a de Polignac number, because 21164031 - 2¹ = 21164029 is a prime.

It is a super-2 number, since 2×21164031² = 895832416337922, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21163995 and 21164013.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21164051) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 22021 + ... + 22961.

It is an arithmetic number, because the mean of its divisors is an integer number (805410).

Almost surely, 2^21164031 is an apocalyptic number.

21164031 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21164031 is a deficient number, since it is larger than the sum of its proper divisors (17495649).

21164031 is a wasteful number, since it uses less digits than its factorization.

21164031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 981 (or 968 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

The square root of 21164031 is about 4600.4381313088. The cubic root of 21164031 is about 276.6088873067.

The spelling of 21164031 in words is "twenty-one million, one hundred sixty-four thousand, thirty-one".