2155863690 has 192 divisors, whose sum is σ = 6191677440. Its totient is φ = 518348160.

The previous prime is 2155863679. The next prime is 2155863701. The reversal of 2155863690 is 963685512.

2155863690 is a `hidden beast` number, since 2 + 1 + 5 + 5 + 8 + 636 + 9 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (2155863679) and next prime (2155863701).

It is a super-2 number, since 2×2155863690² = 9295496499720832200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 3551367 + ... + 3551973.

It is an arithmetic number, because the mean of its divisors is an integer number (32248320).

Almost surely, 2^2155863690 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2155863690, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3095838720).

2155863690 is an abundant number, since it is smaller than the sum of its proper divisors (4035813750).

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

2155863690 is a wasteful number, since it uses less digits than its factorization.

2155863690 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 737 (or 734 counting only the distinct ones).

The product of its (nonzero) digits is 388800, while the sum is 45.

The square root of 2155863690 is about 46431.2792199397. The cubic root of 2155863690 is about 1291.8351562286.

The spelling of 2155863690 in words is "two billion, one hundred fifty-five million, eight hundred sixty-three thousand, six hundred ninety".