21549804392 has 8 divisors (see below), whose sum is σ = 40405883250. Its totient is φ = 10774902192.

The previous prime is 21549804347. The next prime is 21549804421. The reversal of 21549804392 is 29340894512.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 21145231396 + 404572996 = 145414^2 + 20114^2 .

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, 1346862767 + ... + 1346862782.

Almost surely, 2^21549804392 is an apocalyptic number.

It is an amenable number.

21549804392 is a deficient number, since it is larger than the sum of its proper divisors (18856078858).

21549804392 is a wasteful number, since it uses less digits than its factorization.

21549804392 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2693725555 (or 2693725551 counting only the distinct ones).

The product of its (nonzero) digits is 622080, while the sum is 47.

The spelling of 21549804392 in words is "twenty-one billion, five hundred forty-nine million, eight hundred four thousand, three hundred ninety-two".