21203031497 has 2 divisors, whose sum is σ = 21203031498. Its totient is φ = 21203031496.

The previous prime is 21203031491. The next prime is 21203031569. The reversal of 21203031497 is 79413030212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18490288441 + 2712743056 = 135979^2 + 52084^2 .

It is a cyclic number.

It is not a de Polignac number, because 21203031497 - 2¹⁰ = 21203030473 is a prime.

It is a super-2 number, since 2×21203031497² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21203031491) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10601515748 + 10601515749.

It is an arithmetic number, because the mean of its divisors is an integer number (10601515749).

Almost surely, 2^21203031497 is an apocalyptic number.

It is an amenable number.

21203031497 is a deficient number, since it is larger than the sum of its proper divisors (1).

21203031497 is an equidigital number, since it uses as much as digits as its factorization.

21203031497 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9072, while the sum is 32.

The spelling of 21203031497 in words is "twenty-one billion, two hundred three million, thirty-one thousand, four hundred ninety-seven".