77611640 has 64 divisors (see below), whose sum is σ = 179292960. Its totient is φ = 30228480.

The previous prime is 77611621. The next prime is 77611643. The reversal of 77611640 is 4611677.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 77611597 and 77611606.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77611643) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 321920 + ... + 322160.

Almost surely, 2^77611640 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 77611640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (89646480).

77611640 is an abundant number, since it is smaller than the sum of its proper divisors (101681320).

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

77611640 is a wasteful number, since it uses less digits than its factorization.

77611640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 432 (or 428 counting only the distinct ones).

The product of its (nonzero) digits is 7056, while the sum is 32.

The square root of 77611640 is about 8809.7468749108. The cubic root of 77611640 is about 426.5555727473. Note that the first 4 decimals are identical.

The spelling of 77611640 in words is "seventy-seven million, six hundred eleven thousand, six hundred forty".