18862621 has 2 divisors, whose sum is σ = 18862622. Its totient is φ = 18862620.

The previous prime is 18862619. The next prime is 18862631. The reversal of 18862621 is 12626881.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16728100 + 2134521 = 4090^2 + 1461^2 .

It is an emirp because it is prime and its reverse (12626881) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18862621 - 2¹ = 18862619 is a prime.

Together with 18862619, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18862631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9431310 + 9431311.

It is an arithmetic number, because the mean of its divisors is an integer number (9431311).

Almost surely, 2^18862621 is an apocalyptic number.

It is an amenable number.

18862621 is a deficient number, since it is larger than the sum of its proper divisors (1).

18862621 is an equidigital number, since it uses as much as digits as its factorization.

18862621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9216, while the sum is 34.

The square root of 18862621 is about 4343.1119027720. Note that the first 3 decimals coincide. The cubic root of 18862621 is about 266.1954816482.

The spelling of 18862621 in words is "eighteen million, eight hundred sixty-two thousand, six hundred twenty-one".