77787990 has 144 divisors (see below), whose sum is σ = 243285120. Its totient is φ = 17176320.

The previous prime is 77787973. The next prime is 77788003. The reversal of 77787990 is 9978777.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 136426 + ... + 136994.

It is an arithmetic number, because the mean of its divisors is an integer number (1689480).

Almost surely, 2^77787990 is an apocalyptic number.

77787990 is a gapful number since it is divisible by the number (70) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 77787990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (121642560).

77787990 is an abundant number, since it is smaller than the sum of its proper divisors (165497130).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

77787990 is a wasteful number, since it uses less digits than its factorization.

77787990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 627 (or 617 counting only the distinct ones).

The product of its (nonzero) digits is 1555848, while the sum is 54.

The square root of 77787990 is about 8819.7499964568. The cubic root of 77787990 is about 426.8784030721.

The spelling of 77787990 in words is "seventy-seven million, seven hundred eighty-seven thousand, nine hundred ninety".