2151915978 has 16 divisors (see below), whose sum is σ = 4306546080. Its totient is φ = 716852976.

The previous prime is 2151915943. The next prime is 2151916001. The reversal of 2151915978 is 8795191512.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 102708 + ... + 121871.

It is an arithmetic number, because the mean of its divisors is an integer number (269159130).

Almost surely, 2^2151915978 is an apocalyptic number.

2151915978 is an abundant number, since it is smaller than the sum of its proper divisors (2154630102).

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

2151915978 is a wasteful number, since it uses less digits than its factorization.

2151915978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 226181.

The product of its digits is 226800, while the sum is 48.

The square root of 2151915978 is about 46388.7483987227. The cubic root of 2151915978 is about 1291.0461593526.

The spelling of 2151915978 in words is "two billion, one hundred fifty-one million, nine hundred fifteen thousand, nine hundred seventy-eight".