641988406 has 16 divisors (see below), whose sum is σ = 992716560. Its totient is φ = 311148000.

The previous prime is 641988401. The next prime is 641988449. The reversal of 641988406 is 604889146.

It is a super-2 number, since 2×641988406² = 824298226876841672, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (641988401) 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, 3781 + ... + 36031.

It is an arithmetic number, because the mean of its divisors is an integer number (62044785).

Almost surely, 2^641988406 is an apocalyptic number.

641988406 is a deficient number, since it is larger than the sum of its proper divisors (350728154).

641988406 is a wasteful number, since it uses less digits than its factorization.

641988406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32559.

The product of its (nonzero) digits is 331776, while the sum is 46.

The square root of 641988406 is about 25337.4901282665. The cubic root of 641988406 is about 862.6654305936.

The spelling of 641988406 in words is "six hundred forty-one million, nine hundred eighty-eight thousand, four hundred six".