78661220 has 24 divisors (see below), whose sum is σ = 180206208. Its totient is φ = 28604000.

The previous prime is 78661213. The next prime is 78661237. The reversal of 78661220 is 2216687.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 178556 + ... + 178995.

It is an arithmetic number, because the mean of its divisors is an integer number (7508592).

Almost surely, 2^78661220 is an apocalyptic number.

It is an amenable number.

78661220 is an abundant number, since it is smaller than the sum of its proper divisors (101544988).

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

78661220 is a wasteful number, since it uses less digits than its factorization.

78661220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 357571 (or 357569 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 32.

The square root of 78661220 is about 8869.1160777160. The cubic root of 78661220 is about 428.4698090284.

The spelling of 78661220 in words is "seventy-eight million, six hundred sixty-one thousand, two hundred twenty".