21617461 has 2 divisors, whose sum is σ = 21617462. Its totient is φ = 21617460.

The previous prime is 21617413. The next prime is 21617501. The reversal of 21617461 is 16471612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13003236 + 8614225 = 3606^2 + 2935^2 .

It is a cyclic number.

It is not a de Polignac number, because 21617461 - 2⁹ = 21616949 is a prime.

It is equal to p_1366543 and since 21617461 and 1366543 have the same sum of digits, it is a Honaker prime.

It is a plaindrome in base 11.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21617411) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10808730 + 10808731.

It is an arithmetic number, because the mean of its divisors is an integer number (10808731).

Almost surely, 2^21617461 is an apocalyptic number.

It is an amenable number.

21617461 is a deficient number, since it is larger than the sum of its proper divisors (1).

21617461 is an equidigital number, since it uses as much as digits as its factorization.

21617461 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2016, while the sum is 28.

The square root of 21617461 is about 4649.4581404719. The cubic root of 21617461 is about 278.5703531219.

The spelling of 21617461 in words is "twenty-one million, six hundred seventeen thousand, four hundred sixty-one".