781315920 has 480 divisors, whose sum is σ = 3467992320. Its totient is φ = 152616960.

The previous prime is 781315907. The next prime is 781315933. The reversal of 781315920 is 29513187.

It is an interprime number because it is at equal distance from previous prime (781315907) and next prime (781315933).

It is a super-2 number, since 2×781315920² = 1220909133690892800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 942066 + ... + 942894.

It is an arithmetic number, because the mean of its divisors is an integer number (7224984).

Almost surely, 2^781315920 is an apocalyptic number.

781315920 is a gapful number since it is divisible by the number (70) 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 781315920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1733996160).

781315920 is an abundant number, since it is smaller than the sum of its proper divisors (2686676400).

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

781315920 is a wasteful number, since it uses less digits than its factorization.

781315920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 883 (or 874 counting only the distinct ones).

The product of its (nonzero) digits is 15120, while the sum is 36.

The square root of 781315920 is about 27952.0289066822. The cubic root of 781315920 is about 921.0337780762.

The spelling of 781315920 in words is "seven hundred eighty-one million, three hundred fifteen thousand, nine hundred twenty".