18121651 has 2 divisors, whose sum is σ = 18121652. Its totient is φ = 18121650.

The previous prime is 18121633. The next prime is 18121667. The reversal of 18121651 is 15612181.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 18121651 - 2¹⁷ = 17990579 is a prime.

It is not a weakly prime, because it can be changed into another prime (18121151) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9060825 + 9060826.

It is an arithmetic number, because the mean of its divisors is an integer number (9060826).

Almost surely, 2^18121651 is an apocalyptic number.

18121651 is a deficient number, since it is larger than the sum of its proper divisors (1).

18121651 is an equidigital number, since it uses as much as digits as its factorization.

18121651 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 480, while the sum is 25.

The square root of 18121651 is about 4256.9532532082. The cubic root of 18121651 is about 262.6632139929.

The spelling of 18121651 in words is "eighteen million, one hundred twenty-one thousand, six hundred fifty-one".