77479920 has 120 divisors (see below), whose sum is σ = 297394656. Its totient is φ = 17708544.

The previous prime is 77479901. The next prime is 77479973. The reversal of 77479920 is 2997477.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (120).

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 Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2647 + ... + 12726.

Almost surely, 2^77479920 is an apocalyptic number.

77479920 is a gapful number since it is divisible by the number (70) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 77479920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (148697328).

77479920 is an abundant number, since it is smaller than the sum of its proper divisors (219914736).

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

77479920 is a wasteful number, since it uses less digits than its factorization.

77479920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15399 (or 15390 counting only the distinct ones).

The product of its (nonzero) digits is 222264, while the sum is 45.

The square root of 77479920 is about 8802.2678895839. The cubic root of 77479920 is about 426.3141239316.

The spelling of 77479920 in words is "seventy-seven million, four hundred seventy-nine thousand, nine hundred twenty".