71997631440 has 640 divisors, whose sum is σ = 271223783424. Its totient is φ = 15455232000.

The previous prime is 71997631429. The next prime is 71997631441. The reversal of 71997631440 is 4413679917.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71997631441) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 416171194 + ... + 416171366.

Almost surely, 2^71997631440 is an apocalyptic number.

71997631440 is a gapful number since it is divisible by the number (70) 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 71997631440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (135611891712).

71997631440 is an abundant number, since it is smaller than the sum of its proper divisors (199226151984).

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

71997631440 is a wasteful number, since it uses less digits than its factorization.

71997631440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 419 (or 413 counting only the distinct ones).

The product of its (nonzero) digits is 1143072, while the sum is 51.

The spelling of 71997631440 in words is "seventy-one billion, nine hundred ninety-seven million, six hundred thirty-one thousand, four hundred forty".