18207735421 has 2 divisors, whose sum is σ = 18207735422. Its totient is φ = 18207735420.

The previous prime is 18207735419. The next prime is 18207735451. The reversal of 18207735421 is 12453770281.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15117932025 + 3089803396 = 122955^2 + 55586^2 .

It is a cyclic number.

It is not a de Polignac number, because 18207735421 - 2¹ = 18207735419 is a prime.

It is a super-2 number, since 2×18207735421² (a number of 21 digits) contains 22 as substring.

Together with 18207735419, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18207735451) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9103867710 + 9103867711.

It is an arithmetic number, because the mean of its divisors is an integer number (9103867711).

Almost surely, 2^18207735421 is an apocalyptic number.

It is an amenable number.

18207735421 is a deficient number, since it is larger than the sum of its proper divisors (1).

18207735421 is an equidigital number, since it uses as much as digits as its factorization.

18207735421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 94080, while the sum is 40.

The spelling of 18207735421 in words is "eighteen billion, two hundred seven million, seven hundred thirty-five thousand, four hundred twenty-one".