21123000187 has 2 divisors, whose sum is σ = 21123000188. Its totient is φ = 21123000186.

The previous prime is 21123000181. The next prime is 21123000229. The reversal of 21123000187 is 78100032112.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21123000187 - 2²³ = 21114611579 is a prime.

It is a super-2 number, since 2×21123000187² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21123000181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10561500093 + 10561500094.

It is an arithmetic number, because the mean of its divisors is an integer number (10561500094).

Almost surely, 2^21123000187 is an apocalyptic number.

21123000187 is a deficient number, since it is larger than the sum of its proper divisors (1).

21123000187 is an equidigital number, since it uses as much as digits as its factorization.

21123000187 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 672, while the sum is 25.

Adding to 21123000187 its reverse (78100032112), we get a palindrome (99223032299).

The spelling of 21123000187 in words is "twenty-one billion, one hundred twenty-three million, one hundred eighty-seven", and thus it is an aban number.