201891997440 has 864 divisors, whose sum is σ = 817108131840. Its totient is φ = 45076414464.

The previous prime is 201891997429. The next prime is 201891997469. The reversal of 201891997440 is 44799198102.

201891997440 is a `hidden beast` number, since 2 + 0 + 1 + 8 + 9 + 199 + 7 + 440 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 905345169 + ... + 905345391.

Almost surely, 2^201891997440 is an apocalyptic number.

201891997440 is a gapful number since it is divisible by the number (20) 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 201891997440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (408554065920).

201891997440 is an abundant number, since it is smaller than the sum of its proper divisors (615216134400).

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

201891997440 is a wasteful number, since it uses less digits than its factorization.

201891997440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 469 (or 452 counting only the distinct ones).

The product of its (nonzero) digits is 1306368, while the sum is 54.

The spelling of 201891997440 in words is "two hundred one billion, eight hundred ninety-one million, nine hundred ninety-seven thousand, four hundred forty".