645842291 has 16 divisors (see below), whose sum is σ = 703624320. Its totient is φ = 590392320.

The previous prime is 645842213. The next prime is 645842293. The reversal of 645842291 is 192248546.

It is not a de Polignac number, because 645842291 - 2²² = 641647987 is a prime.

It is a super-2 number, since 2×645842291² = 834224529688257362, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (41).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (645842293) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 164645 + ... + 168521.

It is an arithmetic number, because the mean of its divisors is an integer number (43976520).

Almost surely, 2^645842291 is an apocalyptic number.

645842291 is a deficient number, since it is larger than the sum of its proper divisors (57782029).

645842291 is a wasteful number, since it uses less digits than its factorization.

645842291 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4174.

The product of its digits is 138240, while the sum is 41.

The square root of 645842291 is about 25413.4273760939. The cubic root of 645842291 is about 864.3881942393.

The spelling of 645842291 in words is "six hundred forty-five million, eight hundred forty-two thousand, two hundred ninety-one".