21213097 has 2 divisors, whose sum is σ = 21213098. Its totient is φ = 21213096.

The previous prime is 21213089. The next prime is 21213109. The reversal of 21213097 is 79031212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14561856 + 6651241 = 3816^2 + 2579^2 .

It is a cyclic number.

It is not a de Polignac number, because 21213097 - 2³ = 21213089 is a prime.

It is not a weakly prime, because it can be changed into another prime (21213047) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10606548 + 10606549.

It is an arithmetic number, because the mean of its divisors is an integer number (10606549).

Almost surely, 2^21213097 is an apocalyptic number.

It is an amenable number.

21213097 is a deficient number, since it is larger than the sum of its proper divisors (1).

21213097 is an equidigital number, since it uses as much as digits as its factorization.

21213097 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 756, while the sum is 25.

The square root of 21213097 is about 4605.7677970128. The cubic root of 21213097 is about 276.8224826719.

The spelling of 21213097 in words is "twenty-one million, two hundred thirteen thousand, ninety-seven".