2101287978 has 24 divisors (see below), whose sum is σ = 4610424000. Its totient is φ = 691562664.

The previous prime is 2101287977. The next prime is 2101287989. The reversal of 2101287978 is 8797821012.

It is a super-2 number, since 2×2101287978² = 8830822332974656968, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (2101287971) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 737428 + ... + 740271.

It is an arithmetic number, because the mean of its divisors is an integer number (192101000).

Almost surely, 2^2101287978 is an apocalyptic number.

2101287978 is an abundant number, since it is smaller than the sum of its proper divisors (2509136022).

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

2101287978 is a wasteful number, since it uses less digits than its factorization.

2101287978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1477786 (or 1477783 counting only the distinct ones).

The product of its (nonzero) digits is 112896, while the sum is 45.

The square root of 2101287978 is about 45839.8077875551. The cubic root of 2101287978 is about 1280.8409143066.

The spelling of 2101287978 in words is "two billion, one hundred one million, two hundred eighty-seven thousand, nine hundred seventy-eight".