1406405666 has 4 divisors (see below), whose sum is σ = 2109608502. Its totient is φ = 703202832.

The previous prime is 1406405653. The next prime is 1406405677. The reversal of 1406405666 is 6665046041.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 6665046041 = 37273 ⋅178817.

It can be written as a sum of positive squares in only one way, i.e., 1341683641 + 64722025 = 36629^2 + 8045^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 351601415 + ... + 351601418.

Almost surely, 2^1406405666 is an apocalyptic number.

1406405666 is a deficient number, since it is larger than the sum of its proper divisors (703202836).

1406405666 is an equidigital number, since it uses as much as digits as its factorization.

1406405666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 703202835.

The product of its (nonzero) digits is 103680, while the sum is 38.

The square root of 1406405666 is about 37502.0754892313. The cubic root of 1406405666 is about 1120.3925245126.

The spelling of 1406405666 in words is "one billion, four hundred six million, four hundred five thousand, six hundred sixty-six".