2181287564 has 6 divisors (see below), whose sum is σ = 3817253244. Its totient is φ = 1090643780.

The previous prime is 2181287551. The next prime is 2181287567. The reversal of 2181287564 is 4657821812.

It is a super-2 number, since 2×2181287564² = 9516030873722108192, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (2181287567) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 272660942 + ... + 272660949.

It is an arithmetic number, because the mean of its divisors is an integer number (636208874).

Almost surely, 2^2181287564 is an apocalyptic number.

It is an amenable number.

2181287564 is a deficient number, since it is larger than the sum of its proper divisors (1635965680).

2181287564 is a wasteful number, since it uses less digits than its factorization.

2181287564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 545321895 (or 545321893 counting only the distinct ones).

The product of its digits is 215040, while the sum is 44.

The square root of 2181287564 is about 46704.2563799061. The cubic root of 2181287564 is about 1296.8934826874.

The spelling of 2181287564 in words is "two billion, one hundred eighty-one million, two hundred eighty-seven thousand, five hundred sixty-four".