71987664 has 120 divisors (see below), whose sum is σ = 218938368. Its totient is φ = 20321280.

The previous prime is 71987651. The next prime is 71987687. The reversal of 71987664 is 46678917.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 298584 + ... + 298824.

Almost surely, 2^71987664 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 71987664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (109469184).

71987664 is an abundant number, since it is smaller than the sum of its proper divisors (146950704).

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

71987664 is a wasteful number, since it uses less digits than its factorization.

71987664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 393 (or 380 counting only the distinct ones).

The product of its digits is 508032, while the sum is 48.

The square root of 71987664 is about 8484.5544373290. The cubic root of 71987664 is about 415.9930040737.

The spelling of 71987664 in words is "seventy-one million, nine hundred eighty-seven thousand, six hundred sixty-four".