641561554 has 8 divisors (see below), whose sum is σ = 993385728. Its totient is φ = 310432980.

The previous prime is 641561549. The next prime is 641561561. The reversal of 641561554 is 455165146.

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

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 5173822 + ... + 5173945.

It is an arithmetic number, because the mean of its divisors is an integer number (124173216).

Almost surely, 2^641561554 is an apocalyptic number.

641561554 is a deficient number, since it is larger than the sum of its proper divisors (351824174).

641561554 is a wasteful number, since it uses less digits than its factorization.

641561554 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10347800.

The product of its digits is 72000, while the sum is 37.

The square root of 641561554 is about 25329.0653992602. The cubic root of 641561554 is about 862.4741955173.

The spelling of 641561554 in words is "six hundred forty-one million, five hundred sixty-one thousand, five hundred fifty-four".