780400355581 has 48 divisors (see below), whose sum is σ = 1033559403840. Its totient is φ = 581937861120.

The previous prime is 780400355557. The next prime is 780400355621. The reversal of 780400355581 is 185553004087.

It is not a de Polignac number, because 780400355581 - 2⁵ = 780400355549 is a prime.

It is a super-2 number, since 2×780400355581² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (780400355521) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1545390 + ... + 1987216.

It is an arithmetic number, because the mean of its divisors is an integer number (21532487580).

Almost surely, 2^780400355581 is an apocalyptic number.

It is an amenable number.

780400355581 is a deficient number, since it is larger than the sum of its proper divisors (253159048259).

780400355581 is a wasteful number, since it uses less digits than its factorization.

780400355581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 441994 (or 441987 counting only the distinct ones).

The product of its (nonzero) digits is 672000, while the sum is 46.

The spelling of 780400355581 in words is "seven hundred eighty billion, four hundred million, three hundred fifty-five thousand, five hundred eighty-one".