18621437 has 2 divisors, whose sum is σ = 18621438. Its totient is φ = 18621436.

The previous prime is 18621433. The next prime is 18621457. The reversal of 18621437 is 73412681.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15912121 + 2709316 = 3989^2 + 1646^2 .

It is a cyclic number.

It is not a de Polignac number, because 18621437 - 2² = 18621433 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18621431) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9310718 + 9310719.

It is an arithmetic number, because the mean of its divisors is an integer number (9310719).

Almost surely, 2^18621437 is an apocalyptic number.

It is an amenable number.

18621437 is a deficient number, since it is larger than the sum of its proper divisors (1).

18621437 is an equidigital number, since it uses as much as digits as its factorization.

18621437 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8064, while the sum is 32.

The square root of 18621437 is about 4315.2563075674. The cubic root of 18621437 is about 265.0560555441.

The spelling of 18621437 in words is "eighteen million, six hundred twenty-one thousand, four hundred thirty-seven".