21371558 has 16 divisors (see below), whose sum is σ = 35259840. Its totient is φ = 9653376.

The previous prime is 21371551. The next prime is 21371569. The reversal of 21371558 is 85517312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21371551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7523 + ... + 9966.

It is an arithmetic number, because the mean of its divisors is an integer number (2203740).

Almost surely, 2^21371558 is an apocalyptic number.

21371558 is a deficient number, since it is larger than the sum of its proper divisors (13888282).

21371558 is a wasteful number, since it uses less digits than its factorization.

21371558 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17551.

The product of its digits is 8400, while the sum is 32.

The square root of 21371558 is about 4622.9382431523. The cubic root of 21371558 is about 277.5100578017.

The spelling of 21371558 in words is "twenty-one million, three hundred seventy-one thousand, five hundred fifty-eight".