78121680 has 320 divisors, whose sum is σ = 308313600. Its totient is φ = 16257024.

The previous prime is 78121657. The next prime is 78121697. The reversal of 78121680 is 8612187.

It is a happy number.

It is a super-2 number, since 2×78121680² = 12205993772044800, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1070124 + ... + 1070196.

It is an arithmetic number, because the mean of its divisors is an integer number (963480).

Almost surely, 2^78121680 is an apocalyptic number.

78121680 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 78121680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (154156800).

78121680 is an abundant number, since it is smaller than the sum of its proper divisors (230191920).

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

78121680 is a wasteful number, since it uses less digits than its factorization.

78121680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123 (or 103 counting only the distinct ones).

The product of its (nonzero) digits is 5376, while the sum is 33.

The square root of 78121680 is about 8838.6469552755. The cubic root of 78121680 is about 427.4879309886.

The spelling of 78121680 in words is "seventy-eight million, one hundred twenty-one thousand, six hundred eighty".