2121864864 has 48 divisors (see below), whose sum is σ = 6365596608. Its totient is φ = 606246912.

The previous prime is 2121864853. The next prime is 2121864887. The reversal of 2121864864 is 4684681212.

It is a tau number, because it is divible by the number of its divisors (48).

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1578097 + ... + 1579440.

It is an arithmetic number, because the mean of its divisors is an integer number (132616596).

Almost surely, 2^2121864864 is an apocalyptic number.

2121864864 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

2121864864 is an abundant number, since it is smaller than the sum of its proper divisors (4243731744).

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

2121864864 is a wasteful number, since it uses less digits than its factorization.

2121864864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3157557 (or 3157549 counting only the distinct ones).

The product of its digits is 147456, while the sum is 42.

The square root of 2121864864 is about 46063.7044103055. The cubic root of 2121864864 is about 1285.0082239427.

The spelling of 2121864864 in words is "two billion, one hundred twenty-one million, eight hundred sixty-four thousand, eight hundred sixty-four".