1028639664 has 120 divisors (see below), whose sum is σ = 3184209392. Its totient is φ = 307929600.

The previous prime is 1028639659. The next prime is 1028639669. The reversal of 1028639664 is 4669368201.

1028639664 is a `hidden beast` number, since 1 + 0 + 2 + 8 + 639 + 6 + 6 + 4 = 666.

It is an interprime number because it is at equal distance from previous prime (1028639659) and next prime (1028639669).

It is not an unprimeable number, because it can be changed into a prime (1028639669) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 61839 + ... + 76689.

Almost surely, 2^1028639664 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1028639664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1592104696).

1028639664 is an abundant number, since it is smaller than the sum of its proper divisors (2155569728).

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

1028639664 is a wasteful number, since it uses less digits than its factorization.

1028639664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14915 (or 14906 counting only the distinct ones).

The product of its (nonzero) digits is 373248, while the sum is 45.

The square root of 1028639664 is about 32072.4128184956. The cubic root of 1028639664 is about 1009.4568409124.

The spelling of 1028639664 in words is "one billion, twenty-eight million, six hundred thirty-nine thousand, six hundred sixty-four".