21945356 has 6 divisors (see below), whose sum is σ = 38404380. Its totient is φ = 10972676.

The previous prime is 21945347. The next prime is 21945367. The reversal of 21945356 is 65354912.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2743166 + ... + 2743173.

It is an arithmetic number, because the mean of its divisors is an integer number (6400730).

Almost surely, 2^21945356 is an apocalyptic number.

It is an amenable number.

21945356 is a deficient number, since it is larger than the sum of its proper divisors (16459024).

21945356 is a wasteful number, since it uses less digits than its factorization.

21945356 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5486343 (or 5486341 counting only the distinct ones).

The product of its digits is 32400, while the sum is 35.

The square root of 21945356 is about 4684.5870682484. The cubic root of 21945356 is about 279.9717488503.

The spelling of 21945356 in words is "twenty-one million, nine hundred forty-five thousand, three hundred fifty-six".