668021790276 has 135 divisors (see below), whose sum is σ = 1855804350477. Its totient is φ = 209497000320.

The previous prime is 668021790257. The next prime is 668021790287. The reversal of 668021790276 is 672097120866.

The square root of 668021790276 is 817326.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 520086168900 + 147935621376 = 721170^2 + 384624^2 .

It is a super-2 number, since 2×668021790276² (a number of 24 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 250100421 + ... + 250103091.

Almost surely, 2^668021790276 is an apocalyptic number.

668021790276 is the 817326-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 668021790276

668021790276 is an abundant number, since it is smaller than the sum of its proper divisors (1187782560201).

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

668021790276 is an equidigital number, since it uses as much as digits as its factorization.

668021790276 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5392 (or 2693 counting only the distinct ones).

The product of its (nonzero) digits is 3048192, while the sum is 54.

The spelling of 668021790276 in words is "six hundred sixty-eight billion, twenty-one million, seven hundred ninety thousand, two hundred seventy-six".