21389392 has 20 divisors (see below), whose sum is σ = 41847520. Its totient is φ = 10590048.

The previous prime is 21389377. The next prime is 21389393. The reversal of 21389392 is 29398312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21389393) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4842 + ... + 8137.

It is an arithmetic number, because the mean of its divisors is an integer number (2092376).

Almost surely, 2^21389392 is an apocalyptic number.

It is an amenable number.

21389392 is a deficient number, since it is larger than the sum of its proper divisors (20458128).

21389392 is a wasteful number, since it uses less digits than its factorization.

21389392 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13090 (or 13084 counting only the distinct ones).

The product of its digits is 23328, while the sum is 37.

The square root of 21389392 is about 4624.8667007818. The cubic root of 21389392 is about 277.5872279418.

The spelling of 21389392 in words is "twenty-one million, three hundred eighty-nine thousand, three hundred ninety-two".