21342473 has 2 divisors, whose sum is σ = 21342474. Its totient is φ = 21342472.

The previous prime is 21342457. The next prime is 21342479. The reversal of 21342473 is 37424312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19245769 + 2096704 = 4387^2 + 1448^2 .

It is a cyclic number.

It is not a de Polignac number, because 21342473 - 2⁴ = 21342457 is a prime.

It is a super-3 number, since 3×21342473³ (a number of 23 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (21342479) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10671236 + 10671237.

It is an arithmetic number, because the mean of its divisors is an integer number (10671237).

Almost surely, 2^21342473 is an apocalyptic number.

It is an amenable number.

21342473 is a deficient number, since it is larger than the sum of its proper divisors (1).

21342473 is an equidigital number, since it uses as much as digits as its factorization.

21342473 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4032, while the sum is 26.

The square root of 21342473 is about 4619.7914455092. The cubic root of 21342473 is about 277.3841109038.

Adding to 21342473 its reverse (37424312), we get a palindrome (58766785).

The spelling of 21342473 in words is "twenty-one million, three hundred forty-two thousand, four hundred seventy-three".