21740073 has 4 divisors (see below), whose sum is σ = 28986768. Its totient is φ = 14493380.

The previous prime is 21740063. The next prime is 21740101. The reversal of 21740073 is 37004712.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21740073 - 2¹⁰ = 21739049 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21740003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3623343 + ... + 3623348.

It is an arithmetic number, because the mean of its divisors is an integer number (7246692).

Almost surely, 2^21740073 is an apocalyptic number.

It is an amenable number.

21740073 is a deficient number, since it is larger than the sum of its proper divisors (7246695).

21740073 is an equidigital number, since it uses as much as digits as its factorization.

21740073 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7246694.

The product of its (nonzero) digits is 1176, while the sum is 24.

The square root of 21740073 is about 4662.6251189646. The cubic root of 21740073 is about 279.0960345652.

Adding to 21740073 its reverse (37004712), we get a palindrome (58744785).

The spelling of 21740073 in words is "twenty-one million, seven hundred forty thousand, seventy-three".