21461173 has 2 divisors, whose sum is σ = 21461174. Its totient is φ = 21461172.

The previous prime is 21461137. The next prime is 21461179. The reversal of 21461173 is 37116412.

Together with previous prime (21461137) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17489124 + 3972049 = 4182^2 + 1993^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21461173 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21461179) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10730586 + 10730587.

It is an arithmetic number, because the mean of its divisors is an integer number (10730587).

Almost surely, 2^21461173 is an apocalyptic number.

It is an amenable number.

21461173 is a deficient number, since it is larger than the sum of its proper divisors (1).

21461173 is an equidigital number, since it uses as much as digits as its factorization.

21461173 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1008, while the sum is 25.

The square root of 21461173 is about 4632.6205327007. The cubic root of 21461173 is about 277.8974010228.

Adding to 21461173 its reverse (37116412), we get a palindrome (58577585).

The spelling of 21461173 in words is "twenty-one million, four hundred sixty-one thousand, one hundred seventy-three".