90251207640 has 320 divisors, whose sum is σ = 348340608000. Its totient is φ = 20727394560.

The previous prime is 90251207623. The next prime is 90251207677. The reversal of 90251207640 is 4670215209.

90251207640 is a `hidden beast` number, since 9 + 0 + 2 + 5 + 1 + 2 + 0 + 7 + 640 = 666.

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 = 90251207595 and 90251207604.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 610521 + ... + 743799.

It is an arithmetic number, because the mean of its divisors is an integer number (1088564400).

Almost surely, 2^90251207640 is an apocalyptic number.

90251207640 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 90251207640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (174170304000).

90251207640 is an abundant number, since it is smaller than the sum of its proper divisors (258089400360).

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

90251207640 is a wasteful number, since it uses less digits than its factorization.

90251207640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 133332 (or 133319 counting only the distinct ones).

The product of its (nonzero) digits is 30240, while the sum is 36.

The spelling of 90251207640 in words is "ninety billion, two hundred fifty-one million, two hundred seven thousand, six hundred forty".