646545890 has 16 divisors (see below), whose sum is σ = 1164379320. Its totient is φ = 258485760.

The previous prime is 646545877. The next prime is 646545901. The reversal of 646545890 is 98545646.

It can be written as a sum of positive squares in 4 ways, for example, as 502521889 + 144024001 = 22417^2 + 12001^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5276 + ... + 36344.

Almost surely, 2^646545890 is an apocalyptic number.

646545890 is a deficient number, since it is larger than the sum of its proper divisors (517833430).

646545890 is a wasteful number, since it uses less digits than its factorization.

646545890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33157.

The product of its (nonzero) digits is 1036800, while the sum is 47.

The square root of 646545890 is about 25427.2666639574. The cubic root of 646545890 is about 864.7019766978.

The spelling of 646545890 in words is "six hundred forty-six million, five hundred forty-five thousand, eight hundred ninety".