643475551 has 12 divisors (see below), whose sum is σ = 685685728. Its totient is φ = 603735552.

The previous prime is 643475533. The next prime is 643475563. The reversal of 643475551 is 155574346.

It is not a de Polignac number, because 643475551 - 2¹¹ = 643473503 is a prime.

It is a hoax number, since the sum of its digits (40) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643470551) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 94090 + ... + 100696.

Almost surely, 2^643475551 is an apocalyptic number.

643475551 is a deficient number, since it is larger than the sum of its proper divisors (42210177).

643475551 is a wasteful number, since it uses less digits than its factorization.

643475551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6978 (or 6961 counting only the distinct ones).

The product of its digits is 252000, while the sum is 40.

The square root of 643475551 is about 25366.8198834619. The cubic root of 643475551 is about 863.3310289323.

The spelling of 643475551 in words is "six hundred forty-three million, four hundred seventy-five thousand, five hundred fifty-one".