18621901 has 2 divisors, whose sum is σ = 18621902. Its totient is φ = 18621900.

The previous prime is 18621899. The next prime is 18621929. The reversal of 18621901 is 10912681.

It is a happy number.

It is an a-pointer prime, because the next prime (18621929) can be obtained adding 18621901 to its sum of digits (28).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17056900 + 1565001 = 4130^2 + 1251^2 .

It is a cyclic number.

It is not a de Polignac number, because 18621901 - 2¹ = 18621899 is a prime.

Together with 18621899, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18621901.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18621931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9310950 + 9310951.

It is an arithmetic number, because the mean of its divisors is an integer number (9310951).

Almost surely, 2^18621901 is an apocalyptic number.

It is an amenable number.

18621901 is a deficient number, since it is larger than the sum of its proper divisors (1).

18621901 is an equidigital number, since it uses as much as digits as its factorization.

18621901 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864, while the sum is 28.

The square root of 18621901 is about 4315.3100699718. The cubic root of 18621901 is about 265.0582570389.

The spelling of 18621901 in words is "eighteen million, six hundred twenty-one thousand, nine hundred one".