22721729 has 4 divisors (see below), whose sum is σ = 23454720. Its totient is φ = 21988740.

The previous prime is 22721717. The next prime is 22721731. The reversal of 22721729 is 92712722.

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 a de Polignac number, because none of the positive numbers 2^k-22721729 is a prime.

It is a super-4 number, since 4×22721729⁴ (a number of 31 digits) contains 4444 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 22721695 and 22721704.

It is not an unprimeable number, because it can be changed into a prime (22721029) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 366449 + ... + 366510.

It is an arithmetic number, because the mean of its divisors is an integer number (5863680).

Almost surely, 2^22721729 is an apocalyptic number.

It is an amenable number.

22721729 is a deficient number, since it is larger than the sum of its proper divisors (732991).

22721729 is an equidigital number, since it uses as much as digits as its factorization.

22721729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 732990.

The product of its digits is 7056, while the sum is 32.

The square root of 22721729 is about 4766.7314797458. The cubic root of 22721729 is about 283.2351344434.

The spelling of 22721729 in words is "twenty-two million, seven hundred twenty-one thousand, seven hundred twenty-nine".