640406541 has 16 divisors (see below), whose sum is σ = 904737600. Its totient is φ = 401541888.

The previous prime is 640406539. The next prime is 640406563. The reversal of 640406541 is 145604046.

It is not a de Polignac number, because 640406541 - 2¹ = 640406539 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 640406499 and 640406508.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640406521) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 87730 + ... + 94748.

It is an arithmetic number, because the mean of its divisors is an integer number (56546100).

Almost surely, 2^640406541 is an apocalyptic number.

It is an amenable number.

640406541 is a deficient number, since it is larger than the sum of its proper divisors (264331059).

640406541 is a wasteful number, since it uses less digits than its factorization.

640406541 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8828.

The product of its (nonzero) digits is 11520, while the sum is 30.

The square root of 640406541 is about 25306.2549777718. The cubic root of 640406541 is about 861.9563094800.

The spelling of 640406541 in words is "six hundred forty million, four hundred six thousand, five hundred forty-one".