21539839400452 has 6 divisors (see below), whose sum is σ = 37694718950798. Its totient is φ = 10769919700224.

The previous prime is 21539839400437. The next prime is 21539839400473. The reversal of 21539839400452 is 25400493893512.

It can be written as a sum of positive squares in only one way, i.e., 21261376332036 + 278463068416 = 4611006^2 + 527696^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21539839400393 and 21539839400402.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2692479925053 + ... + 2692479925060.

Almost surely, 2^{21539839400452} is an apocalyptic number.

It is an amenable number.

21539839400452 is a deficient number, since it is larger than the sum of its proper divisors (16154879550346).

21539839400452 is a wasteful number, since it uses less digits than its factorization.

21539839400452 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5384959850117 (or 5384959850115 counting only the distinct ones).

The product of its (nonzero) digits is 9331200, while the sum is 55.

The spelling of 21539839400452 in words is "twenty-one trillion, five hundred thirty-nine billion, eight hundred thirty-nine million, four hundred thousand, four hundred fifty-two".