21164494 has 8 divisors (see below), whose sum is σ = 34188840. Its totient is φ = 9768216.

The previous prime is 21164489. The next prime is 21164501. The reversal of 21164494 is 49446112.

It is a sphenic number, since it is the product of 3 distinct primes.

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 3 ways as a sum of consecutive naturals, for example, 406984 + ... + 407035.

It is an arithmetic number, because the mean of its divisors is an integer number (4273605).

Almost surely, 2^21164494 is an apocalyptic number.

21164494 is a deficient number, since it is larger than the sum of its proper divisors (13024346).

21164494 is a wasteful number, since it uses less digits than its factorization.

21164494 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 814034.

The product of its digits is 6912, while the sum is 31.

The square root of 21164494 is about 4600.4884523276. The cubic root of 21164494 is about 276.6109043922.

The spelling of 21164494 in words is "twenty-one million, one hundred sixty-four thousand, four hundred ninety-four".