18774748721 has 8 divisors (see below), whose sum is σ = 18923578344. Its totient is φ = 18626460160.

The previous prime is 18774748703. The next prime is 18774748739. The reversal of 18774748721 is 12784747781.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (18774748703) and next prime (18774748739).

It can be written as a sum of positive squares in 4 ways, for example, as 8281000000 + 10493748721 = 91000^2 + 102439^2 .

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 18774748721 - 2²² = 18770554417 is a prime.

It is a super-2 number, since 2×18774748721² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18774748771) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 65450 + ... + 204531.

It is an arithmetic number, because the mean of its divisors is an integer number (2365447293).

Almost surely, 2^18774748721 is an apocalyptic number.

It is an amenable number.

18774748721 is a deficient number, since it is larger than the sum of its proper divisors (148829623).

18774748721 is a wasteful number, since it uses less digits than its factorization.

18774748721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 270531.

The product of its digits is 4917248, while the sum is 56.

The spelling of 18774748721 in words is "eighteen billion, seven hundred seventy-four million, seven hundred forty-eight thousand, seven hundred twenty-one".