5621256904561 has 9 divisors (see below), whose sum is σ = 5652916709643. Its totient is φ = 5589773471160.

The previous prime is 5621256904541. The next prime is 5621256904567. The reversal of 5621256904561 is 1654096521265.

The square root of 5621256904561 is 2370919.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 61941752161 + 5559315152400 = 248881^2 + 2357820^2 .

It is not a de Polignac number, because 5621256904561 - 2³³ = 5612666969969 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 5621256904499 and 5621256904508.

It is not an unprimeable number, because it can be changed into a prime (5621256904567) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 429129790 + ... + 429142888.

It is an arithmetic number, because the mean of its divisors is an integer number (628101856627).

Almost surely, 2^{5621256904561} is an apocalyptic number.

5621256904561 is the 2370919-th square number.

5621256904561 is the 1185460-th centered octagonal number.

It is an amenable number.

5621256904561 is a deficient number, since it is larger than the sum of its proper divisors (31659805082).

5621256904561 is an frugal number, since it uses more digits than its factorization.

5621256904561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26560 (or 13280 counting only the distinct ones).

The product of its (nonzero) digits is 3888000, while the sum is 52.

The spelling of 5621256904561 in words is "five trillion, six hundred twenty-one billion, two hundred fifty-six million, nine hundred four thousand, five hundred sixty-one".