2172787645 has 12 divisors (see below), whose sum is σ = 3033034524. Its totient is φ = 1489911360.

The previous prime is 2172787637. The next prime is 2172787657. The reversal of 2172787645 is 5467872712.

It can be written as a sum of positive squares in 2 ways, for example, as 776569689 + 1396217956 = 27867^2 + 37366^2 .

It is not a de Polignac number, because 2172787645 - 2³ = 2172787637 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (49).

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4434016 + ... + 4434505.

It is an arithmetic number, because the mean of its divisors is an integer number (252752877).

Almost surely, 2^2172787645 is an apocalyptic number.

It is an amenable number.

2172787645 is a deficient number, since it is larger than the sum of its proper divisors (860246879).

2172787645 is an equidigital number, since it uses as much as digits as its factorization.

2172787645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8868540 (or 8868533 counting only the distinct ones).

The product of its digits is 1317120, while the sum is 49.

The square root of 2172787645 is about 46613.1702955291. The cubic root of 2172787645 is about 1295.2067359257.

The spelling of 2172787645 in words is "two billion, one hundred seventy-two million, seven hundred eighty-seven thousand, six hundred forty-five".