16666236401 has 4 divisors (see below), whose sum is σ = 16669793904. Its totient is φ = 16662678900.

The previous prime is 16666236347. The next prime is 16666236409. The reversal of 16666236401 is 10463266661.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 10463266661 = 31 ⋅337524731.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16666236401 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16666236409) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1771715 + ... + 1781096.

It is an arithmetic number, because the mean of its divisors is an integer number (4167448476).

Almost surely, 2^16666236401 is an apocalyptic number.

It is an amenable number.

16666236401 is a deficient number, since it is larger than the sum of its proper divisors (3557503).

16666236401 is an equidigital number, since it uses as much as digits as its factorization.

16666236401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3557502.

The product of its (nonzero) digits is 186624, while the sum is 41.

The spelling of 16666236401 in words is "sixteen billion, six hundred sixty-six million, two hundred thirty-six thousand, four hundred one".