91970640 has 280 divisors, whose sum is σ = 341540640. Its totient is φ = 22954752.

The previous prime is 91970633. The next prime is 91970651. The reversal of 91970640 is 4607919.

91970640 is a `hidden beast` number, since 9 + 1 + 9 + 7 + 0 + 640 = 666.

It is a super-3 number, since 3×91970640³ (a number of 25 digits) contains 333 as substring.

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

It is a junction number, because it is equal to n+sod(n) for n = 91970595 and 91970604.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 1108039 + ... + 1108121.

It is an arithmetic number, because the mean of its divisors is an integer number (1219788).

Almost surely, 2^91970640 is an apocalyptic number.

91970640 is a gapful number since it is divisible by the number (90) 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 91970640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (170770320).

91970640 is an abundant number, since it is smaller than the sum of its proper divisors (249570000).

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

91970640 is a wasteful number, since it uses less digits than its factorization.

91970640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133 (or 112 counting only the distinct ones).

The product of its (nonzero) digits is 13608, while the sum is 36.

The square root of 91970640 is about 9590.1324286998. The cubic root of 91970640 is about 451.3877161430.

The spelling of 91970640 in words is "ninety-one million, nine hundred seventy thousand, six hundred forty".