1981518264 has 384 divisors, whose sum is σ = 6577459200. Its totient is φ = 536659200.

The previous prime is 1981518263. The next prime is 1981518271. The reversal of 1981518264 is 4628151891.

It is a happy number.

Its product of digits (138240) is a multiple of the sum of its prime factors (128).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1981518263) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 63919929 + ... + 63919959.

It is an arithmetic number, because the mean of its divisors is an integer number (17128800).

Almost surely, 2^1981518264 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 1981518264, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3288729600).

1981518264 is an abundant number, since it is smaller than the sum of its proper divisors (4595940936).

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

1981518264 is a wasteful number, since it uses less digits than its factorization.

1981518264 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128 (or 99 counting only the distinct ones).

The product of its digits is 138240, while the sum is 45.

The square root of 1981518264 is about 44514.2478763822. The cubic root of 1981518264 is about 1256.0281124112.

The spelling of 1981518264 in words is "one billion, nine hundred eighty-one million, five hundred eighteen thousand, two hundred sixty-four".