21350951989 has 2 divisors, whose sum is σ = 21350951990. Its totient is φ = 21350951988.

The previous prime is 21350951929. The next prime is 21350952043. The reversal of 21350951989 is 98915905312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20337612100 + 1013339889 = 142610^2 + 31833^2 .

It is a cyclic number.

It is not a de Polignac number, because 21350951989 - 2¹³ = 21350943797 is a prime.

It is a super-2 number, since 2×21350951989² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21350951929) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10675475994 + 10675475995.

It is an arithmetic number, because the mean of its divisors is an integer number (10675475995).

Almost surely, 2^21350951989 is an apocalyptic number.

It is an amenable number.

21350951989 is a deficient number, since it is larger than the sum of its proper divisors (1).

21350951989 is an equidigital number, since it uses as much as digits as its factorization.

21350951989 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 874800, while the sum is 52.

The spelling of 21350951989 in words is "twenty-one billion, three hundred fifty million, nine hundred fifty-one thousand, nine hundred eighty-nine".