78121572 has 12 divisors (see below), whose sum is σ = 182283696. Its totient is φ = 26040520.

The previous prime is 78121553. The next prime is 78121573. The reversal of 78121572 is 27512187.

It is a tau number, because it is divible by the number of its divisors (12).

It is a super-2 number, since 2×78121572² = 12205960023502368, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (78121573) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3255054 + ... + 3255077.

It is an arithmetic number, because the mean of its divisors is an integer number (15190308).

Almost surely, 2^78121572 is an apocalyptic number.

It is an amenable number.

78121572 is an abundant number, since it is smaller than the sum of its proper divisors (104162124).

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

78121572 is a wasteful number, since it uses less digits than its factorization.

78121572 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6510138 (or 6510136 counting only the distinct ones).

The product of its digits is 7840, while the sum is 33.

The square root of 78121572 is about 8838.6408457409. The cubic root of 78121572 is about 427.4877339937.

The spelling of 78121572 in words is "seventy-eight million, one hundred twenty-one thousand, five hundred seventy-two".