643155431 has 8 divisors (see below), whose sum is σ = 647738880. Its totient is φ = 638587872.

The previous prime is 643155427. The next prime is 643155437. The reversal of 643155431 is 134551346.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 643155431 - 2² = 643155427 is a prime.

It is a super-2 number, since 2×643155431² = 827297816849591522, 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 (643155437) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 84041 + ... + 91373.

It is an arithmetic number, because the mean of its divisors is an integer number (80967360).

Almost surely, 2^643155431 is an apocalyptic number.

643155431 is a deficient number, since it is larger than the sum of its proper divisors (4583449).

643155431 is a wasteful number, since it uses less digits than its factorization.

643155431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7945.

The product of its digits is 21600, while the sum is 32.

The square root of 643155431 is about 25360.5092811639. The cubic root of 643155431 is about 863.1878401864.

The spelling of 643155431 in words is "six hundred forty-three million, one hundred fifty-five thousand, four hundred thirty-one".