21740392 has 8 divisors (see below), whose sum is σ = 40763250. Its totient is φ = 10870192.

The previous prime is 21740387. The next prime is 21740417. The reversal of 21740392 is 29304712.

It can be written as a sum of positive squares in only one way, i.e., 17355556 + 4384836 = 4166^2 + 2094^2 .

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

It is a self number, because there is not a number n which added to its sum of digits gives 21740392.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1358767 + ... + 1358782.

Almost surely, 2^21740392 is an apocalyptic number.

It is an amenable number.

21740392 is a deficient number, since it is larger than the sum of its proper divisors (19022858).

21740392 is a wasteful number, since it uses less digits than its factorization.

21740392 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2717555 (or 2717551 counting only the distinct ones).

The product of its (nonzero) digits is 3024, while the sum is 28.

The square root of 21740392 is about 4662.6593270364. The cubic root of 21740392 is about 279.0973996511.

The spelling of 21740392 in words is "twenty-one million, seven hundred forty thousand, three hundred ninety-two".