2551561506406 has 64 divisors (see below), whose sum is σ = 4467569649984. Its totient is φ = 1080056217600.

The previous prime is 2551561506367. The next prime is 2551561506407. The reversal of 2551561506406 is 6046051651552.

It is a happy number.

It is a super-2 number, since 2×2551561506406² (a number of 26 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2551561506407) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 230758830 + ... + 230769886.

It is an arithmetic number, because the mean of its divisors is an integer number (69805775781).

Almost surely, 2^{2551561506406} is an apocalyptic number.

2551561506406 is a deficient number, since it is larger than the sum of its proper divisors (1916008143578).

2551561506406 is a wasteful number, since it uses less digits than its factorization.

2551561506406 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17545.

The product of its (nonzero) digits is 1080000, while the sum is 46.

The spelling of 2551561506406 in words is "two trillion, five hundred fifty-one billion, five hundred sixty-one million, five hundred six thousand, four hundred six".