668551520 has 384 divisors, whose sum is σ = 2142878976. Its totient is φ = 191102976.

The previous prime is 668551517. The next prime is 668551579. The reversal of 668551520 is 25155866.

668551520 = 2311² + 2312² + ... + 2429².

It is a super-2 number, since 2×668551520² = 893922269788620800, 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 63 ways as a sum of consecutive naturals, for example, 9158204 + ... + 9158276.

It is an arithmetic number, because the mean of its divisors is an integer number (5580414).

Almost surely, 2^668551520 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 668551520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1071439488).

668551520 is an abundant number, since it is smaller than the sum of its proper divisors (1474327456).

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

668551520 is a wasteful number, since it uses less digits than its factorization.

668551520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 162 (or 154 counting only the distinct ones).

The product of its (nonzero) digits is 72000, while the sum is 38.

The square root of 668551520 is about 25856.3632400228. The cubic root of 668551520 is about 874.4029755919.

The spelling of 668551520 in words is "six hundred sixty-eight million, five hundred fifty-one thousand, five hundred twenty".