21610943 has 2 divisors, whose sum is σ = 21610944. Its totient is φ = 21610942.

The previous prime is 21610931. The next prime is 21610949. The reversal of 21610943 is 34901612.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21610943 - 2¹⁰ = 21609919 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21610949) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10805471 + 10805472.

It is an arithmetic number, because the mean of its divisors is an integer number (10805472).

Almost surely, 2^21610943 is an apocalyptic number.

21610943 is a deficient number, since it is larger than the sum of its proper divisors (1).

21610943 is an equidigital number, since it uses as much as digits as its factorization.

21610943 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1296, while the sum is 26.

The square root of 21610943 is about 4648.7571457326. The cubic root of 21610943 is about 278.5423525459.

The spelling of 21610943 in words is "twenty-one million, six hundred ten thousand, nine hundred forty-three".