21813097 has 2 divisors, whose sum is σ = 21813098. Its totient is φ = 21813096.

The previous prime is 21813089. The next prime is 21813101. The reversal of 21813097 is 79031812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10949481 + 10863616 = 3309^2 + 3296^2 .

It is a cyclic number.

It is not a de Polignac number, because 21813097 - 2³ = 21813089 is a prime.

It is a super-2 number, since 2×21813097² = 951622401462818, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21813037) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10906548 + 10906549.

It is an arithmetic number, because the mean of its divisors is an integer number (10906549).

Almost surely, 2^21813097 is an apocalyptic number.

It is an amenable number.

21813097 is a deficient number, since it is larger than the sum of its proper divisors (1).

21813097 is an equidigital number, since it uses as much as digits as its factorization.

21813097 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3024, while the sum is 31.

The square root of 21813097 is about 4670.4493359847. The cubic root of 21813097 is about 279.4081759887.

The spelling of 21813097 in words is "twenty-one million, eight hundred thirteen thousand, ninety-seven".