18311641 has 2 divisors, whose sum is σ = 18311642. Its totient is φ = 18311640.

The previous prime is 18311627. The next prime is 18311693. The reversal of 18311641 is 14611381.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11758041 + 6553600 = 3429^2 + 2560^2 .

It is a cyclic number.

It is not a de Polignac number, because 18311641 - 2⁵ = 18311609 is a prime.

It is a super-2 number, since 2×18311641² = 670632392225762, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (18311141) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9155820 + 9155821.

It is an arithmetic number, because the mean of its divisors is an integer number (9155821).

Almost surely, 2^18311641 is an apocalyptic number.

It is an amenable number.

18311641 is a deficient number, since it is larger than the sum of its proper divisors (1).

18311641 is an equidigital number, since it uses as much as digits as its factorization.

18311641 is an evil number, because the sum of its binary digits is even.

The product of its digits is 576, while the sum is 25.

The square root of 18311641 is about 4279.2103243472. The cubic root of 18311641 is about 263.5779576270.

The spelling of 18311641 in words is "eighteen million, three hundred eleven thousand, six hundred forty-one".