21123976 has 8 divisors (see below), whose sum is σ = 39607470. Its totient is φ = 10561984.

The previous prime is 21123917. The next prime is 21123983. The reversal of 21123976 is 67932112.

It can be written as a sum of positive squares in only one way, i.e., 20921476 + 202500 = 4574^2 + 450^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1320241 + ... + 1320256.

Almost surely, 2^21123976 is an apocalyptic number.

It is an amenable number.

21123976 is a deficient number, since it is larger than the sum of its proper divisors (18483494).

21123976 is a wasteful number, since it uses less digits than its factorization.

21123976 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2640503 (or 2640499 counting only the distinct ones).

The product of its digits is 4536, while the sum is 31.

The square root of 21123976 is about 4596.0826798481. The cubic root of 21123976 is about 276.4342739724.

The spelling of 21123976 in words is "twenty-one million, one hundred twenty-three thousand, nine hundred seventy-six".