21977632 has 12 divisors (see below), whose sum is σ = 43268526. Its totient is φ = 10988800.

The previous prime is 21977609. The next prime is 21977633. The reversal of 21977632 is 23677912.

It can be written as a sum of positive squares in only one way, i.e., 16613776 + 5363856 = 4076^2 + 2316^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21977591 and 21977600.

It is not an unprimeable number, because it can be changed into a prime (21977633) by changing a digit.

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 as a sum of consecutive naturals, namely, 343369 + ... + 343432.

Almost surely, 2^21977632 is an apocalyptic number.

It is an amenable number.

21977632 is a deficient number, since it is larger than the sum of its proper divisors (21290894).

21977632 is an equidigital number, since it uses as much as digits as its factorization.

21977632 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 686811 (or 686803 counting only the distinct ones).

The product of its digits is 31752, while the sum is 37.

The square root of 21977632 is about 4688.0307166229. The cubic root of 21977632 is about 280.1089372031.

The spelling of 21977632 in words is "twenty-one million, nine hundred seventy-seven thousand, six hundred thirty-two".