645556111 has 24 divisors (see below), whose sum is σ = 704638080. Its totient is φ = 590124480.

The previous prime is 645556099. The next prime is 645556117. The reversal of 645556111 is 111655546.

It is not a de Polignac number, because 645556111 - 2¹⁹ = 645031823 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645556117) 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, 2280976 + ... + 2281258.

It is an arithmetic number, because the mean of its divisors is an integer number (29359920).

Almost surely, 2^645556111 is an apocalyptic number.

645556111 is a deficient number, since it is larger than the sum of its proper divisors (59081969).

645556111 is a wasteful number, since it uses less digits than its factorization.

645556111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 447 (or 406 counting only the distinct ones).

The product of its digits is 18000, while the sum is 34.

The square root of 645556111 is about 25407.7962641391. The cubic root of 645556111 is about 864.2605019924.

The spelling of 645556111 in words is "six hundred forty-five million, five hundred fifty-six thousand, one hundred eleven".