21173004 has 36 divisors (see below), whose sum is σ = 53660880. Its totient is φ = 7039200.

The previous prime is 21172999. The next prime is 21173021. The reversal of 21173004 is 40037112.

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 24817 + ... + 25655.

It is an arithmetic number, because the mean of its divisors is an integer number (1490580).

Almost surely, 2^21173004 is an apocalyptic number.

It is an amenable number.

21173004 is an abundant number, since it is smaller than the sum of its proper divisors (32487876).

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

21173004 is a wasteful number, since it uses less digits than its factorization.

21173004 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1550 (or 1545 counting only the distinct ones).

The product of its (nonzero) digits is 168, while the sum is 18.

The square root of 21173004 is about 4601.4132611623. The cubic root of 21173004 is about 276.6479734471.

The spelling of 21173004 in words is "twenty-one million, one hundred seventy-three thousand, four".