78281220 has 24 divisors (see below), whose sum is σ = 219187584. Its totient is φ = 20874976.

The previous prime is 78281219. The next prime is 78281221. The reversal of 78281220 is 2218287.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (78281219) and next prime (78281221).

It is a super-2 number, since 2×78281220² = 12255898809376800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is not an unprimeable number, because it can be changed into a prime (78281221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 652284 + ... + 652403.

It is an arithmetic number, because the mean of its divisors is an integer number (9132816).

Almost surely, 2^78281220 is an apocalyptic number.

It is an amenable number.

78281220 is an abundant number, since it is smaller than the sum of its proper divisors (140906364).

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

78281220 is a wasteful number, since it uses less digits than its factorization.

78281220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1304699 (or 1304697 counting only the distinct ones).

The product of its (nonzero) digits is 3584, while the sum is 30.

The square root of 78281220 is about 8847.6674892313. The cubic root of 78281220 is about 427.7787382274.

The spelling of 78281220 in words is "seventy-eight million, two hundred eighty-one thousand, two hundred twenty".