21371388 has 24 divisors (see below), whose sum is σ = 49969920. Its totient is φ = 7109040.

The previous prime is 21371377. The next prime is 21371401. The reversal of 21371388 is 88317312.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5293 + ... + 8411.

It is an arithmetic number, because the mean of its divisors is an integer number (2082080).

Almost surely, 2^21371388 is an apocalyptic number.

It is an amenable number.

21371388 is an abundant number, since it is smaller than the sum of its proper divisors (28598532).

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

21371388 is a wasteful number, since it uses less digits than its factorization.

21371388 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3697 (or 3695 counting only the distinct ones).

The product of its digits is 8064, while the sum is 33.

The square root of 21371388 is about 4622.9198565409. The cubic root of 21371388 is about 277.5093219821.

The spelling of 21371388 in words is "twenty-one million, three hundred seventy-one thousand, three hundred eighty-eight".