2147255721 has 24 divisors (see below), whose sum is σ = 3515977920. Its totient is φ = 1251840096.

The previous prime is 2147255717. The next prime is 2147255749. The reversal of 2147255721 is 1275527412.

2147255721 is a `hidden beast` number, since 2 + 14 + 72 + 5 + 572 + 1 = 666.

It is not a de Polignac number, because 2147255721 - 2² = 2147255717 is a prime.

It is a super-2 number, since 2×2147255721² = 9221414262734459682, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (2147255701) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 480741 + ... + 485186.

It is an arithmetic number, because the mean of its divisors is an integer number (146499080).

Almost surely, 2^2147255721 is an apocalyptic number.

It is an amenable number.

2147255721 is a deficient number, since it is larger than the sum of its proper divisors (1368722199).

2147255721 is a wasteful number, since it uses less digits than its factorization.

2147255721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 965965 (or 965962 counting only the distinct ones).

The product of its digits is 39200, while the sum is 36.

The square root of 2147255721 is about 46338.4907069706. The cubic root of 2147255721 is about 1290.1135090312.

The spelling of 2147255721 in words is "two billion, one hundred forty-seven million, two hundred fifty-five thousand, seven hundred twenty-one".