261628045551 has 10 divisors (see below), whose sum is σ = 390827080512. Its totient is φ = 174418696980.

The previous prime is 261628045537. The next prime is 261628045559. The reversal of 261628045551 is 155540826162.

261628045551 is a `hidden beast` number, since 2 + 6 + 16 + 2 + 80 + 4 + 5 + 551 = 666.

It is not a de Polignac number, because 261628045551 - 2¹⁰ = 261628044527 is a prime.

It is a super-2 number, since 2×261628045551² (a number of 24 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 261628045497 and 261628045506.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261628045559) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 1614987855 + ... + 1614988016.

Almost surely, 2^261628045551 is an apocalyptic number.

261628045551 is a deficient number, since it is larger than the sum of its proper divisors (129199034961).

261628045551 is an equidigital number, since it uses as much as digits as its factorization.

261628045551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3229975883 (or 3229975874 counting only the distinct ones).

The product of its (nonzero) digits is 576000, while the sum is 45.

The spelling of 261628045551 in words is "two hundred sixty-one billion, six hundred twenty-eight million, forty-five thousand, five hundred fifty-one".