78991224 has 64 divisors (see below), whose sum is σ = 219555840. Its totient is φ = 23518080.

The previous prime is 78991219. The next prime is 78991277. The reversal of 78991224 is 42219987.

It is a super-2 number, since 2×78991224² = 12479226938036352, 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 15 ways as a sum of consecutive naturals, for example, 5589 + ... + 13755.

It is an arithmetic number, because the mean of its divisors is an integer number (3430560).

Almost surely, 2^78991224 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 78991224, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (109777920).

78991224 is an abundant number, since it is smaller than the sum of its proper divisors (140564616).

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

78991224 is a wasteful number, since it uses less digits than its factorization.

78991224 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8220 (or 8216 counting only the distinct ones).

The product of its digits is 72576, while the sum is 42.

The square root of 78991224 is about 8887.7007150331. The cubic root of 78991224 is about 429.0681533313.

The spelling of 78991224 in words is "seventy-eight million, nine hundred ninety-one thousand, two hundred twenty-four".