55661604352521 has 16 divisors (see below), whose sum is σ = 75137158474560. Its totient is φ = 36647220896000.

The previous prime is 55661604352507. The next prime is 55661604352537. The reversal of 55661604352521 is 12525340616655.

It is a cyclic number.

It is not a de Polignac number, because 55661604352521 - 2¹⁷ = 55661604221449 is a prime.

It is not an unprimeable number, because it can be changed into a prime (55661604356521) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 40276980 + ... + 41636021.

It is an arithmetic number, because the mean of its divisors is an integer number (4696072404660).

Almost surely, 2^{55661604352521} is an apocalyptic number.

It is an amenable number.

55661604352521 is a deficient number, since it is larger than the sum of its proper divisors (19475554122039).

55661604352521 is a wasteful number, since it uses less digits than its factorization.

55661604352521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81915816.

The product of its (nonzero) digits is 6480000, while the sum is 51.

The spelling of 55661604352521 in words is "fifty-five trillion, six hundred sixty-one billion, six hundred four million, three hundred fifty-two thousand, five hundred twenty-one".