21311394 has 32 divisors (see below), whose sum is σ = 46080384. Its totient is φ = 6531840.

The previous prime is 21311393. The next prime is 21311399. The reversal of 21311394 is 49311312.

It is not an unprimeable number, because it can be changed into a prime (21311393) 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, 33459 + ... + 34089.

It is an arithmetic number, because the mean of its divisors is an integer number (1440012).

Almost surely, 2^21311394 is an apocalyptic number.

21311394 is an abundant number, since it is smaller than the sum of its proper divisors (24768990).

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

21311394 is a wasteful number, since it uses less digits than its factorization.

21311394 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1082.

The product of its digits is 648, while the sum is 24.

The square root of 21311394 is about 4616.4265400849. The cubic root of 21311394 is about 277.2494028542.

The spelling of 21311394 in words is "twenty-one million, three hundred eleven thousand, three hundred ninety-four".