18973517 has 2 divisors, whose sum is σ = 18973518. Its totient is φ = 18973516.

The previous prime is 18973499. The next prime is 18973531. The reversal of 18973517 is 71537981.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17732521 + 1240996 = 4211^2 + 1114^2 .

It is a cyclic number.

It is not a de Polignac number, because 18973517 - 2¹² = 18969421 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18973217) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9486758 + 9486759.

It is an arithmetic number, because the mean of its divisors is an integer number (9486759).

Almost surely, 2^18973517 is an apocalyptic number.

It is an amenable number.

18973517 is a deficient number, since it is larger than the sum of its proper divisors (1).

18973517 is an equidigital number, since it uses as much as digits as its factorization.

18973517 is an evil number, because the sum of its binary digits is even.

The product of its digits is 52920, while the sum is 41.

The square root of 18973517 is about 4355.8600758059. The cubic root of 18973517 is about 266.7161295401.

The spelling of 18973517 in words is "eighteen million, nine hundred seventy-three thousand, five hundred seventeen".