18862121 has 2 divisors, whose sum is σ = 18862122. Its totient is φ = 18862120.

The previous prime is 18862033. The next prime is 18862127. The reversal of 18862121 is 12126881.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17106496 + 1755625 = 4136^2 + 1325^2 .

It is a cyclic number.

It is not a de Polignac number, because 18862121 - 2¹⁰ = 18861097 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (18862127) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9431060 + 9431061.

It is an arithmetic number, because the mean of its divisors is an integer number (9431061).

Almost surely, 2^18862121 is an apocalyptic number.

It is an amenable number.

18862121 is a deficient number, since it is larger than the sum of its proper divisors (1).

18862121 is an equidigital number, since it uses as much as digits as its factorization.

18862121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1536, while the sum is 29.

The square root of 18862121 is about 4343.0543399778. The cubic root of 18862121 is about 266.1931295728.

It can be divided in two parts, 1886 and 2121, that multiplied together give a triangular number (4000206 = T₂₈₂₈).

The spelling of 18862121 in words is "eighteen million, eight hundred sixty-two thousand, one hundred twenty-one".