669768640 has 112 divisors (see below), whose sum is σ = 1664354304. Its totient is φ = 256435200.

The previous prime is 669768637. The next prime is 669768653. The reversal of 669768640 is 46867966.

It is a super-2 number, since 2×669768640² = 897180062254899200, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1061125 + ... + 1061755.

Almost surely, 2^669768640 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 669768640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (832177152).

669768640 is an abundant number, since it is smaller than the sum of its proper divisors (994585664).

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

669768640 is a wasteful number, since it uses less digits than its factorization.

669768640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 786 (or 776 counting only the distinct ones).

The product of its (nonzero) digits is 2612736, while the sum is 52.

The square root of 669768640 is about 25879.8887169168. Note that the first 3 decimals coincide. The cubic root of 669768640 is about 874.9332803549.

The spelling of 669768640 in words is "six hundred sixty-nine million, seven hundred sixty-eight thousand, six hundred forty".