21797663 has 2 divisors, whose sum is σ = 21797664. Its totient is φ = 21797662.

The previous prime is 21797651. The next prime is 21797683. The reversal of 21797663 is 36679712.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21797663 - 2⁶ = 21797599 is a prime.

It is a super-2 number, since 2×21797663² = 950276224523138, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21797663.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21797623) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10898831 + 10898832.

It is an arithmetic number, because the mean of its divisors is an integer number (10898832).

Almost surely, 2^21797663 is an apocalyptic number.

21797663 is a deficient number, since it is larger than the sum of its proper divisors (1).

21797663 is an equidigital number, since it uses as much as digits as its factorization.

21797663 is an evil number, because the sum of its binary digits is even.

The product of its digits is 95256, while the sum is 41.

The square root of 21797663 is about 4668.7967400605. The cubic root of 21797663 is about 279.3422614103.

The spelling of 21797663 in words is "twenty-one million, seven hundred ninety-seven thousand, six hundred sixty-three".