781266780 has 216 divisors, whose sum is σ = 2775335472. Its totient is φ = 177375744.

The previous prime is 781266769. The next prime is 781266793. The reversal of 781266780 is 87662187.

It is a super-2 number, since 2×781266780² = 1220755563063136800, 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 an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 2495904 + ... + 2496216.

Almost surely, 2^781266780 is an apocalyptic number.

781266780 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 781266780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1387667736).

781266780 is an abundant number, since it is smaller than the sum of its proper divisors (1994068692).

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

781266780 is a wasteful number, since it uses less digits than its factorization.

781266780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 625 (or 613 counting only the distinct ones).

The product of its (nonzero) digits is 225792, while the sum is 45.

The square root of 781266780 is about 27951.1498869009. The cubic root of 781266780 is about 921.0144685381.

The spelling of 781266780 in words is "seven hundred eighty-one million, two hundred sixty-six thousand, seven hundred eighty".