668400442 has 16 divisors (see below), whose sum is σ = 1039224960. Its totient is φ = 322204608.

The previous prime is 668400427. The next prime is 668400451. The reversal of 668400442 is 244004866.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 668400398 and 668400407.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 46767 + ... + 59362.

It is an arithmetic number, because the mean of its divisors is an integer number (64951560).

Almost surely, 2^668400442 is an apocalyptic number.

668400442 is a deficient number, since it is larger than the sum of its proper divisors (370824518).

668400442 is a wasteful number, since it uses less digits than its factorization.

668400442 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 106245.

The product of its (nonzero) digits is 36864, while the sum is 34.

The square root of 668400442 is about 25853.4415890806. The cubic root of 668400442 is about 874.3371053232.

The spelling of 668400442 in words is "six hundred sixty-eight million, four hundred thousand, four hundred forty-two".