16207581421 has 2 divisors, whose sum is σ = 16207581422. Its totient is φ = 16207581420.

The previous prime is 16207581413. The next prime is 16207581449. The reversal of 16207581421 is 12418570261.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 9558972900 + 6648608521 = 97770^2 + 81539^2 .

It is a cyclic number.

It is not a de Polignac number, because 16207581421 - 2³ = 16207581413 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16207588421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8103790710 + 8103790711.

It is an arithmetic number, because the mean of its divisors is an integer number (8103790711).

Almost surely, 2^16207581421 is an apocalyptic number.

It is an amenable number.

16207581421 is a deficient number, since it is larger than the sum of its proper divisors (1).

16207581421 is an equidigital number, since it uses as much as digits as its factorization.

16207581421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 26880, while the sum is 37.

The spelling of 16207581421 in words is "sixteen billion, two hundred seven million, five hundred eighty-one thousand, four hundred twenty-one".