1000666401 has 16 divisors (see below), whose sum is σ = 1536835584. Its totient is φ = 567305424.

The previous prime is 1000666399. The next prime is 1000666409. The reversal of 1000666401 is 1046660001.

It is not a de Polignac number, because 1000666401 - 2¹ = 1000666399 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1000666409) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 184935 + ... + 190268.

It is an arithmetic number, because the mean of its divisors is an integer number (96052224).

Almost surely, 2^1000666401 is an apocalyptic number.

It is an amenable number.

1000666401 is a deficient number, since it is larger than the sum of its proper divisors (536169183).

1000666401 is a wasteful number, since it uses less digits than its factorization.

1000666401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 375340.

The product of its (nonzero) digits is 864, while the sum is 24.

The square root of 1000666401 is about 31633.3115718225. The cubic root of 1000666401 is about 1000.2220843416. Note that the first 3 decimals are identical.

The spelling of 1000666401 in words is "one billion, six hundred sixty-six thousand, four hundred one".