76561861 has 4 divisors (see below), whose sum is σ = 76687372. Its totient is φ = 76436352.

The previous prime is 76561853. The next prime is 76561873. The reversal of 76561861 is 16816567.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 16816567 = 353 ⋅47639.

It can be written as a sum of positive squares in 2 ways, for example, as 23184225 + 53377636 = 4815^2 + 7306^2 .

It is a cyclic number.

It is not a de Polignac number, because 76561861 - 2³ = 76561853 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (76561831) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 61836 + ... + 63061.

It is an arithmetic number, because the mean of its divisors is an integer number (19171843).

Almost surely, 2^76561861 is an apocalyptic number.

It is an amenable number.

76561861 is a deficient number, since it is larger than the sum of its proper divisors (125511).

76561861 is a wasteful number, since it uses less digits than its factorization.

76561861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 125510.

The product of its digits is 60480, while the sum is 40.

The square root of 76561861 is about 8749.9634856381. The cubic root of 76561861 is about 424.6236317336.

It can be divided in two parts, 765 and 61861, that added together give a palindrome (62626).

The spelling of 76561861 in words is "seventy-six million, five hundred sixty-one thousand, eight hundred sixty-one".