21735091949 has 2 divisors, whose sum is σ = 21735091950. Its totient is φ = 21735091948.

The previous prime is 21735091901. The next prime is 21735091979. The reversal of 21735091949 is 94919053712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15126540100 + 6608551849 = 122990^2 + 81293^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21735091949 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21735091897 and 21735091906.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21735091979) 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, 10867545974 + 10867545975.

It is an arithmetic number, because the mean of its divisors is an integer number (10867545975).

Almost surely, 2^21735091949 is an apocalyptic number.

It is an amenable number.

21735091949 is a deficient number, since it is larger than the sum of its proper divisors (1).

21735091949 is an equidigital number, since it uses as much as digits as its factorization.

21735091949 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 612360, while the sum is 50.

The spelling of 21735091949 in words is "twenty-one billion, seven hundred thirty-five million, ninety-one thousand, nine hundred forty-nine".