781940520 has 128 divisors (see below), whose sum is σ = 2670192000. Its totient is φ = 203420160.

The previous prime is 781940519. The next prime is 781940521. The reversal of 781940520 is 25049187.

It is an interprime number because it is at equal distance from previous prime (781940519) and next prime (781940521).

It is a super-2 number, since 2×781940520² = 1222861953635740800, which contains 22 as substring.

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

It is not an unprimeable number, because it can be changed into a prime (781940521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 35451 + ... + 53109.

It is an arithmetic number, because the mean of its divisors is an integer number (20860875).

Almost surely, 2^781940520 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 781940520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1335096000).

781940520 is an abundant number, since it is smaller than the sum of its proper divisors (1888251480).

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

781940520 is a wasteful number, since it uses less digits than its factorization.

781940520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17720 (or 17710 counting only the distinct ones).

The product of its (nonzero) digits is 20160, while the sum is 36.

The square root of 781940520 is about 27963.1993877668. The cubic root of 781940520 is about 921.2791438132.

The spelling of 781940520 in words is "seven hundred eighty-one million, nine hundred forty thousand, five hundred twenty".