87770781 has 12 divisors (see below), whose sum is σ = 144891552. Its totient is φ = 50154696.

The previous prime is 87770777. The next prime is 87770807. The reversal of 87770781 is 18707778.

It is not a de Polignac number, because 87770781 - 2² = 87770777 is a prime.

It is a super-2 number, since 2×87770781² = 15407419994699922, which contains 22 as substring.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (87770581) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 696531 + ... + 696656.

It is an arithmetic number, because the mean of its divisors is an integer number (12074296).

Almost surely, 2^87770781 is an apocalyptic number.

It is an amenable number.

87770781 is a deficient number, since it is larger than the sum of its proper divisors (57120771).

87770781 is a wasteful number, since it uses less digits than its factorization.

87770781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1393200 (or 1393197 counting only the distinct ones).

The product of its (nonzero) digits is 153664, while the sum is 45.

The square root of 87770781 is about 9368.6061396560. The cubic root of 87770781 is about 444.4094864842.

The spelling of 87770781 in words is "eighty-seven million, seven hundred seventy thousand, seven hundred eighty-one".