77521415545 has 12 divisors (see below), whose sum is σ = 108213568164. Its totient is φ = 53157541920.

The previous prime is 77521415509. The next prime is 77521415563. The reversal of 77521415545 is 54551412577.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 25615362304 + 51906053241 = 160048^2 + 227829^2 .

It is not a de Polignac number, because 77521415545 - 2²³ = 77513026937 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 77521415495 and 77521415504.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 158206726 + ... + 158207215.

It is an arithmetic number, because the mean of its divisors is an integer number (9017797347).

Almost surely, 2^77521415545 is an apocalyptic number.

It is an amenable number.

77521415545 is a deficient number, since it is larger than the sum of its proper divisors (30692152619).

77521415545 is a wasteful number, since it uses less digits than its factorization.

77521415545 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 316413960 (or 316413953 counting only the distinct ones).

The product of its digits is 980000, while the sum is 46.

The spelling of 77521415545 in words is "seventy-seven billion, five hundred twenty-one million, four hundred fifteen thousand, five hundred forty-five".