91007784040 has 24 divisors (see below), whose sum is σ = 204771807090. Its totient is φ = 36402350432.

The previous prime is 91007784031. The next prime is 91007784041. The reversal of 91007784040 is 4048770019.

It can be written as a sum of positive squares in only one way, i.e., 81907005636 + 9100778404 = 286194^2 + 95398^2 .

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 91007783984 and 91007784002.

It is not an unprimeable number, because it can be changed into a prime (91007784041) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1884111 + ... + 1931809.

Almost surely, 2^91007784040 is an apocalyptic number.

It is an amenable number.

91007784040 is an abundant number, since it is smaller than the sum of its proper divisors (113764023050).

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

91007784040 is an frugal number, since it uses more digits than its factorization.

91007784040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95409 (or 47706 counting only the distinct ones).

The product of its (nonzero) digits is 56448, while the sum is 40.

Multiplying 91007784040 by its sum of digits (40), we get a square (3640311361600 = 1907960²).

91007784040 divided by its sum of digits (40) gives a square (2275194601 = 47699²).

The spelling of 91007784040 in words is "ninety-one billion, seven million, seven hundred eighty-four thousand, forty".