77137920 has 288 divisors, whose sum is σ = 286191360. Its totient is φ = 19906560.

The previous prime is 77137903. The next prime is 77137937. The reversal of 77137920 is 2973177.

It is an interprime number because it is at equal distance from previous prime (77137903) and next prime (77137937).

It is a tau number, because it is divible by the number of its divisors (288).

It is a Harshad number since it is a multiple of its sum of digits (36).

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, 2488305 + ... + 2488335.

It is an arithmetic number, because the mean of its divisors is an integer number (993720).

Almost surely, 2^77137920 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 77137920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (143095680).

77137920 is an abundant number, since it is smaller than the sum of its proper divisors (209053440).

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

77137920 is an equidigital number, since it uses as much as digits as its factorization.

77137920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73 (or 41 counting only the distinct ones).

The product of its (nonzero) digits is 18522, while the sum is 36.

The square root of 77137920 is about 8782.8195928187. The cubic root of 77137920 is about 425.6859419035.

The spelling of 77137920 in words is "seventy-seven million, one hundred thirty-seven thousand, nine hundred twenty".