646021110 has 256 divisors, whose sum is σ = 1954160640. Its totient is φ = 133539840.

The previous prime is 646021099. The next prime is 646021127. The reversal of 646021110 is 11120646.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 10590480 + ... + 10590540.

It is an arithmetic number, because the mean of its divisors is an integer number (7633440).

Almost surely, 2^646021110 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 646021110, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (977080320).

646021110 is an abundant number, since it is smaller than the sum of its proper divisors (1308139530).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

646021110 is a wasteful number, since it uses less digits than its factorization.

646021110 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 191.

The product of its (nonzero) digits is 288, while the sum is 21.

The square root of 646021110 is about 25416.9453318057. The cubic root of 646021110 is about 864.4679633364.

Adding to 646021110 its reverse (11120646), we get a palindrome (657141756).

The spelling of 646021110 in words is "six hundred forty-six million, twenty-one thousand, one hundred ten".