2172120651 has 64 divisors (see below), whose sum is σ = 3515996160. Its totient is φ = 1320030720.

The previous prime is 2172120649. The next prime is 2172120683. The reversal of 2172120651 is 1560212712.

2172120651 is a `hidden beast` number, since 2 + 1 + 7 + 2 + 1 + 2 + 0 + 651 = 666.

It is not a de Polignac number, because 2172120651 - 2¹ = 2172120649 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (2172120151) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 2307841 + ... + 2308781.

It is an arithmetic number, because the mean of its divisors is an integer number (54937440).

Almost surely, 2^2172120651 is an apocalyptic number.

2172120651 is a deficient number, since it is larger than the sum of its proper divisors (1343875509).

2172120651 is a wasteful number, since it uses less digits than its factorization.

2172120651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1121 (or 1115 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 27.

The square root of 2172120651 is about 46606.0151804464. The cubic root of 2172120651 is about 1295.0741898334.

The spelling of 2172120651 in words is "two billion, one hundred seventy-two million, one hundred twenty thousand, six hundred fifty-one".