21097903061 has 2 divisors, whose sum is σ = 21097903062. Its totient is φ = 21097903060.

The previous prime is 21097903039. The next prime is 21097903063. The reversal of 21097903061 is 16030979012.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15231262225 + 5866640836 = 123415^2 + 76594^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21097903061 is a prime.

Together with 21097903063, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21097903063) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10548951530 + 10548951531.

It is an arithmetic number, because the mean of its divisors is an integer number (10548951531).

Almost surely, 2^21097903061 is an apocalyptic number.

It is an amenable number.

21097903061 is a deficient number, since it is larger than the sum of its proper divisors (1).

21097903061 is an equidigital number, since it uses as much as digits as its factorization.

21097903061 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 20412, while the sum is 38.

The spelling of 21097903061 in words is "twenty-one billion, ninety-seven million, nine hundred three thousand, sixty-one".