2155731900 has 144 divisors (see below), whose sum is σ = 7294366464. Its totient is φ = 481259520.

The previous prime is 2155731899. The next prime is 2155731931. The reversal of 2155731900 is 91375512.

It is a super-2 number, since 2×2155731900² = 9294360049355220000, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 78364 + ... + 102236.

Almost surely, 2^2155731900 is an apocalyptic number.

2155731900 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 2155731900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3647183232).

2155731900 is an abundant number, since it is smaller than the sum of its proper divisors (5138634564).

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

2155731900 is a wasteful number, since it uses less digits than its factorization.

2155731900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23940 (or 23933 counting only the distinct ones).

The product of its (nonzero) digits is 9450, while the sum is 33.

The square root of 2155731900 is about 46429.8600040965. The cubic root of 2155731900 is about 1291.8088319878.

The spelling of 2155731900 in words is "two billion, one hundred fifty-five million, seven hundred thirty-one thousand, nine hundred".