64971601816 has 64 divisors (see below), whose sum is σ = 135045701280. Its totient is φ = 29058478080.

The previous prime is 64971601811. The next prime is 64971601823. The reversal of 64971601816 is 61810617946.

It is a self number, because there is not a number n which added to its sum of digits gives 64971601816.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64971601811) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1454730 + ... + 1498726.

Almost surely, 2^64971601816 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 64971601816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (67522850640).

64971601816 is an abundant number, since it is smaller than the sum of its proper divisors (70074099464).

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

64971601816 is a wasteful number, since it uses less digits than its factorization.

64971601816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44284 (or 44280 counting only the distinct ones).

The product of its (nonzero) digits is 435456, while the sum is 49.

The spelling of 64971601816 in words is "sixty-four billion, nine hundred seventy-one million, six hundred one thousand, eight hundred sixteen".