87913767781 has 4 divisors (see below), whose sum is σ = 100472877472. Its totient is φ = 75354658092.

The previous prime is 87913767779. The next prime is 87913767839. The reversal of 87913767781 is 18776731978.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 87913767781 - 2¹ = 87913767779 is a prime.

It is a super-2 number, since 2×87913767781² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (87913767701) 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, 6279554835 + ... + 6279554848.

It is an arithmetic number, because the mean of its divisors is an integer number (25118219368).

Almost surely, 2^87913767781 is an apocalyptic number.

It is an amenable number.

87913767781 is a deficient number, since it is larger than the sum of its proper divisors (12559109691).

87913767781 is a wasteful number, since it uses less digits than its factorization.

87913767781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12559109690.

The product of its digits is 24893568, while the sum is 64.

The spelling of 87913767781 in words is "eighty-seven billion, nine hundred thirteen million, seven hundred sixty-seven thousand, seven hundred eighty-one".