18774561621 has 8 divisors (see below), whose sum is σ = 25033472800. Its totient is φ = 12516012432.

The previous prime is 18774561607. The next prime is 18774561683. The reversal of 18774561621 is 12616547781.

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

It is not a de Polignac number, because 18774561621 - 2⁷ = 18774561493 is a prime.

It is a super-2 number, since 2×18774561621² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18774561121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 72426 + ... + 206868.

It is an arithmetic number, because the mean of its divisors is an integer number (3129184100).

Almost surely, 2^18774561621 is an apocalyptic number.

It is an amenable number.

18774561621 is a deficient number, since it is larger than the sum of its proper divisors (6258911179).

18774561621 is a wasteful number, since it uses less digits than its factorization.

18774561621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 180995.

The product of its digits is 564480, while the sum is 48.

The spelling of 18774561621 in words is "eighteen billion, seven hundred seventy-four million, five hundred sixty-one thousand, six hundred twenty-one".