77873229825561 has 135 divisors (see below), whose sum is σ = 124779534545127. Its totient is φ = 48389766405120.

The previous prime is 77873229825539. The next prime is 77873229825577. The reversal of 77873229825561 is 16552892237877.

It is a happy number.

The square root of 77873229825561 is 8824581.

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

77873229825561 is a `hidden beast` number, since 7 + 7 + 8 + 7 + 32 + 2 + 9 + 8 + 25 + 561 = 666.

It can be written as a sum of positive squares in 13 ways, for example, as 63003414125961 + 14869815699600 = 7937469^2 + 3856140^2 .

It is not a de Polignac number, because 77873229825561 - 2⁹ = 77873229825049 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 77873229825561.

It is not an unprimeable number, because it can be changed into a prime (77873229825661) by changing a digit.

It is a polite number, since it can be written in 134 ways as a sum of consecutive naturals, for example, 184972042131 + ... + 184972042551.

Almost surely, 2^{77873229825561} is an apocalyptic number.

77873229825561 is the 8824581-st square number.

77873229825561 is the 4412291-st centered octagonal number.

It is an amenable number.

77873229825561 is a deficient number, since it is larger than the sum of its proper divisors (46906304719566).

77873229825561 is an frugal number, since it uses more digits than its factorization.

77873229825561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1162 (or 578 counting only the distinct ones).

The product of its digits is 711244800, while the sum is 72.

The spelling of 77873229825561 in words is "seventy-seven trillion, eight hundred seventy-three billion, two hundred twenty-nine million, eight hundred twenty-five thousand, five hundred sixty-one".