18453991 has 2 divisors, whose sum is σ = 18453992. Its totient is φ = 18453990.

The previous prime is 18453979. The next prime is 18454003. The reversal of 18453991 is 19935481.

It is a balanced prime because it is at equal distance from previous prime (18453979) and next prime (18454003).

It is a cyclic number.

It is not a de Polignac number, because 18453991 - 2⁷ = 18453863 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18453931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9226995 + 9226996.

It is an arithmetic number, because the mean of its divisors is an integer number (9226996).

Almost surely, 2^18453991 is an apocalyptic number.

18453991 is a deficient number, since it is larger than the sum of its proper divisors (1).

18453991 is an equidigital number, since it uses as much as digits as its factorization.

18453991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 38880, while the sum is 40.

The square root of 18453991 is about 4295.8108664139. The cubic root of 18453991 is about 264.2591912303.

The spelling of 18453991 in words is "eighteen million, four hundred fifty-three thousand, nine hundred ninety-one".