21031438 has 16 divisors (see below), whose sum is σ = 32760000. Its totient is φ = 10114272.

The previous prime is 21031433. The next prime is 21031457. The reversal of 21031438 is 83413012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21031433) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19723 + ... + 20761.

It is an arithmetic number, because the mean of its divisors is an integer number (2047500).

Almost surely, 2^21031438 is an apocalyptic number.

21031438 is a deficient number, since it is larger than the sum of its proper divisors (11728562).

21031438 is a wasteful number, since it uses less digits than its factorization.

21031438 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1419.

The product of its (nonzero) digits is 576, while the sum is 22.

The square root of 21031438 is about 4586.0045791517. The cubic root of 21031438 is about 276.0300236890.

The spelling of 21031438 in words is "twenty-one million, thirty-one thousand, four hundred thirty-eight".