18406979 has 2 divisors, whose sum is σ = 18406980. Its totient is φ = 18406978.

The previous prime is 18406951. The next prime is 18406981. The reversal of 18406979 is 97960481.

It is a strong prime.

It is an emirp because it is prime and its reverse (97960481) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18406979 - 2¹² = 18402883 is a prime.

Together with 18406981, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18406919) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9203489 + 9203490.

It is an arithmetic number, because the mean of its divisors is an integer number (9203490).

Almost surely, 2^18406979 is an apocalyptic number.

18406979 is a deficient number, since it is larger than the sum of its proper divisors (1).

18406979 is an equidigital number, since it uses as much as digits as its factorization.

18406979 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 108864, while the sum is 44.

The square root of 18406979 is about 4290.3355346639. The cubic root of 18406979 is about 264.0345981209.

The spelling of 18406979 in words is "eighteen million, four hundred six thousand, nine hundred seventy-nine".