71787020761 has 9 divisors (see below), whose sum is σ = 74355842431. Its totient is φ = 69304104184.

The previous prime is 71787020749. The next prime is 71787020813. The reversal of 71787020761 is 16702078717.

It is a happy number.

The square root of 71787020761 is 267931.

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

It can be written as a sum of positive squares in only one way, i.e., 37643372361 + 34143648400 = 194019^2 + 184780^2 .

It is not a de Polignac number, because 71787020761 - 2²³ = 71778632153 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (71787023761) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 7765380 + ... + 7774618.

Almost surely, 2^71787020761 is an apocalyptic number.

71787020761 is the 267931-st square number.

71787020761 is the 133966-th centered octagonal number.

It is an amenable number.

71787020761 is a deficient number, since it is larger than the sum of its proper divisors (2568821670).

71787020761 is an frugal number, since it uses more digits than its factorization.

71787020761 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18536 (or 9268 counting only the distinct ones).

The product of its (nonzero) digits is 230496, while the sum is 46.

The spelling of 71787020761 in words is "seventy-one billion, seven hundred eighty-seven million, twenty thousand, seven hundred sixty-one".