21301997 has 2 divisors, whose sum is σ = 21301998. Its totient is φ = 21301996.

The previous prime is 21301967. The next prime is 21302027. The reversal of 21301997 is 79910312.

It is a happy number.

21301997 is nontrivially palindromic in base 7.

It is a balanced prime because it is at equal distance from previous prime (21301967) and next prime (21302027).

It can be written as a sum of positive squares in only one way, i.e., 16760836 + 4541161 = 4094^2 + 2131^2 .

It is a cyclic number.

It is not a de Polignac number, because 21301997 - 2⁸ = 21301741 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21301937) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10650998 + 10650999.

It is an arithmetic number, because the mean of its divisors is an integer number (10650999).

Almost surely, 2^21301997 is an apocalyptic number.

It is an amenable number.

21301997 is a deficient number, since it is larger than the sum of its proper divisors (1).

21301997 is an equidigital number, since it uses as much as digits as its factorization.

21301997 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3402, while the sum is 32.

The square root of 21301997 is about 4615.4086492964. The cubic root of 21301997 is about 277.2086469459.

The spelling of 21301997 in words is "twenty-one million, three hundred one thousand, nine hundred ninety-seven".