645673869 has 8 divisors (see below), whose sum is σ = 956553920. Its totient is φ = 430449228.

The previous prime is 645673823. The next prime is 645673891. The reversal of 645673869 is 968376546.

It is not a de Polignac number, because 645673869 - 2⁷ = 645673741 is a prime.

It is a super-2 number, since 2×645673869² = 833789490218858322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645673069) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11956897 + ... + 11956950.

It is an arithmetic number, because the mean of its divisors is an integer number (119569240).

Almost surely, 2^645673869 is an apocalyptic number.

It is an amenable number.

645673869 is a deficient number, since it is larger than the sum of its proper divisors (310880051).

645673869 is a wasteful number, since it uses less digits than its factorization.

645673869 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23913856 (or 23913850 counting only the distinct ones).

The product of its digits is 6531840, while the sum is 54.

The square root of 645673869 is about 25410.1135180463. The cubic root of 645673869 is about 864.3130496583.

The spelling of 645673869 in words is "six hundred forty-five million, six hundred seventy-three thousand, eight hundred sixty-nine".