21371493 has 32 divisors (see below), whose sum is σ = 34578432. Its totient is φ = 11563200.

The previous prime is 21371489. The next prime is 21371509. The reversal of 21371493 is 39417312.

It is not a de Polignac number, because 21371493 - 2² = 21371489 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21371493.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21371423) 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 31 ways as a sum of consecutive naturals, for example, 12496 + ... + 14102.

It is an arithmetic number, because the mean of its divisors is an integer number (1080576).

Almost surely, 2^21371493 is an apocalyptic number.

It is an amenable number.

21371493 is a deficient number, since it is larger than the sum of its proper divisors (13206939).

21371493 is a wasteful number, since it uses less digits than its factorization.

21371493 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1665.

The product of its digits is 4536, while the sum is 30.

The square root of 21371493 is about 4622.9312129860. The cubic root of 21371493 is about 277.5097764594.

The spelling of 21371493 in words is "twenty-one million, three hundred seventy-one thousand, four hundred ninety-three".