813978720 has 240 divisors, whose sum is σ = 2896861968. Its totient is φ = 215239680.

The previous prime is 813978713. The next prime is 813978721. The reversal of 813978720 is 27879318.

It is a tau number, because it is divible by the number of its divisors (240).

It is a super-2 number, since 2×813978720² = 1325122713225676800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (813978721) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 2345587 + ... + 2345933.

Almost surely, 2^813978720 is an apocalyptic number.

813978720 is a gapful number since it is divisible by the number (80) 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 813978720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1448430984).

813978720 is an abundant number, since it is smaller than the sum of its proper divisors (2082883248).

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

813978720 is a wasteful number, since it uses less digits than its factorization.

813978720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 555 (or 538 counting only the distinct ones).

The product of its (nonzero) digits is 169344, while the sum is 45.

The square root of 813978720 is about 28530.3123011298. The cubic root of 813978720 is about 933.6935321734.

The spelling of 813978720 in words is "eight hundred thirteen million, nine hundred seventy-eight thousand, seven hundred twenty".