18421637 has 8 divisors (see below), whose sum is σ = 19950840. Its totient is φ = 16908480.

The previous prime is 18421633. The next prime is 18421639. The reversal of 18421637 is 73612481.

It can be written as a sum of positive squares in 4 ways, for example, as 2172676 + 16248961 = 1474^2 + 4031^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 18421637 - 2² = 18421633 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18421631) 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 in 7 ways as a sum of consecutive naturals, for example, 1562 + ... + 6267.

It is an arithmetic number, because the mean of its divisors is an integer number (2493855).

Almost surely, 2^18421637 is an apocalyptic number.

It is an amenable number.

18421637 is a deficient number, since it is larger than the sum of its proper divisors (1529203).

18421637 is a wasteful number, since it uses less digits than its factorization.

18421637 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8023.

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

The square root of 18421637 is about 4292.0434527157. The cubic root of 18421637 is about 264.1046656077.

The spelling of 18421637 in words is "eighteen million, four hundred twenty-one thousand, six hundred thirty-seven".