2155394640 has 320 divisors, whose sum is σ = 8152621056. Its totient is φ = 459841536.

The previous prime is 2155394639. The next prime is 2155394663. The reversal of 2155394640 is 464935512.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 4655049 + ... + 4655511.

Almost surely, 2^2155394640 is an apocalyptic number.

2155394640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2155394640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4076310528).

2155394640 is an abundant number, since it is smaller than the sum of its proper divisors (5997226416).

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

2155394640 is a wasteful number, since it uses less digits than its factorization.

2155394640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 666 (or 660 counting only the distinct ones).

The product of its (nonzero) digits is 129600, while the sum is 39.

The square root of 2155394640 is about 46426.2279320644. The cubic root of 2155394640 is about 1291.7414614938.

The spelling of 2155394640 in words is "two billion, one hundred fifty-five million, three hundred ninety-four thousand, six hundred forty".