21377684 has 6 divisors (see below), whose sum is σ = 37410954. Its totient is φ = 10688840.

The previous prime is 21377677. The next prime is 21377701. The reversal of 21377684 is 48677312.

It can be written as a sum of positive squares in only one way, i.e., 16224784 + 5152900 = 4028^2 + 2270^2 .

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, 2672207 + ... + 2672214.

It is an arithmetic number, because the mean of its divisors is an integer number (6235159).

Almost surely, 2^21377684 is an apocalyptic number.

It is an amenable number.

21377684 is a deficient number, since it is larger than the sum of its proper divisors (16033270).

21377684 is a wasteful number, since it uses less digits than its factorization.

21377684 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5344425 (or 5344423 counting only the distinct ones).

The product of its digits is 56448, while the sum is 38.

The square root of 21377684 is about 4623.6007613115. The cubic root of 21377684 is about 277.5365706747.

The spelling of 21377684 in words is "twenty-one million, three hundred seventy-seven thousand, six hundred eighty-four".