21312776 has 8 divisors (see below), whose sum is σ = 39961470. Its totient is φ = 10656384.

The previous prime is 21312763. The next prime is 21312787. The reversal of 21312776 is 67721312.

It can be written as a sum of positive squares in only one way, i.e., 20484676 + 828100 = 4526^2 + 910^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1332041 + ... + 1332056.

Almost surely, 2^21312776 is an apocalyptic number.

It is an amenable number.

21312776 is a deficient number, since it is larger than the sum of its proper divisors (18648694).

21312776 is a wasteful number, since it uses less digits than its factorization.

21312776 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2664103 (or 2664099 counting only the distinct ones).

The product of its digits is 3528, while the sum is 29.

The square root of 21312776 is about 4616.5762205340. The cubic root of 21312776 is about 277.2553957422.

The spelling of 21312776 in words is "twenty-one million, three hundred twelve thousand, seven hundred seventy-six".