649187890 has 32 divisors (see below), whose sum is σ = 1264863600. Its totient is φ = 238473984.

The previous prime is 649187879. The next prime is 649187897. The reversal of 649187890 is 98781946.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 319801689 + 329386201 = 17883^2 + 18149^2 .

It is not an unprimeable number, because it can be changed into a prime (649187897) 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, 12936 + ... + 38284.

Almost surely, 2^649187890 is an apocalyptic number.

649187890 is a deficient number, since it is larger than the sum of its proper divisors (615675710).

649187890 is a wasteful number, since it uses less digits than its factorization.

649187890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25566.

The product of its (nonzero) digits is 870912, while the sum is 52.

The square root of 649187890 is about 25479.1658026710. The cubic root of 649187890 is about 865.8781952794.

The spelling of 649187890 in words is "six hundred forty-nine million, one hundred eighty-seven thousand, eight hundred ninety".