21971494 has 16 divisors (see below), whose sum is σ = 33488640. Its totient is φ = 10810240.

The previous prime is 21971489. The next prime is 21971501. The reversal of 21971494 is 49417912.

It is a congruent number.

It is an unprimeable number.

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, 42912 + ... + 43420.

It is an arithmetic number, because the mean of its divisors is an integer number (2093040).

Almost surely, 2^21971494 is an apocalyptic number.

21971494 is a deficient number, since it is larger than the sum of its proper divisors (11517146).

21971494 is a wasteful number, since it uses less digits than its factorization.

21971494 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 815.

The product of its digits is 18144, while the sum is 37.

The square root of 21971494 is about 4687.3760250272. The cubic root of 21971494 is about 280.0828581311.

The spelling of 21971494 in words is "twenty-one million, nine hundred seventy-one thousand, four hundred ninety-four".