77681240 has 64 divisors (see below), whose sum is σ = 215127360. Its totient is φ = 24583680.

The previous prime is 77681231. The next prime is 77681249. The reversal of 77681240 is 4218677.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (77681231) and next prime (77681249).

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a self number, because there is not a number n which added to its sum of digits gives 77681240.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77681249) 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, 7031 + ... + 14310.

It is an arithmetic number, because the mean of its divisors is an integer number (3361365).

Almost surely, 2^77681240 is an apocalyptic number.

77681240 is a gapful number since it is divisible by the number (70) formed by its first and last digit.

It is an amenable number.

77681240 is an abundant number, since it is smaller than the sum of its proper divisors (137446120).

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

77681240 is a wasteful number, since it uses less digits than its factorization.

77681240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21372 (or 21368 counting only the distinct ones).

The product of its (nonzero) digits is 18816, while the sum is 35.

The square root of 77681240 is about 8813.6961599547. The cubic root of 77681240 is about 426.6830424487.

The spelling of 77681240 in words is "seventy-seven million, six hundred eighty-one thousand, two hundred forty".