22011721 has 2 divisors, whose sum is σ = 22011722. Its totient is φ = 22011720.

The previous prime is 22011701. The next prime is 22011727. The reversal of 22011721 is 12711022.

22011721 is nontrivially palindromic in base 15.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13220496 + 8791225 = 3636^2 + 2965^2 .

It is a cyclic number.

It is not a de Polignac number, because 22011721 - 2¹³ = 22003529 is a prime.

It is a super-2 number, since 2×22011721² = 969031722763682, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 22011695 and 22011704.

It is not a weakly prime, because it can be changed into another prime (22011727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11005860 + 11005861.

It is an arithmetic number, because the mean of its divisors is an integer number (11005861).

Almost surely, 2^22011721 is an apocalyptic number.

It is an amenable number.

22011721 is a deficient number, since it is larger than the sum of its proper divisors (1).

22011721 is an equidigital number, since it uses as much as digits as its factorization.

22011721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 56, while the sum is 16.

The square root of 22011721 is about 4691.6650562460. The cubic root of 22011721 is about 280.2536859021.

Adding to 22011721 its reverse (12711022), we get a palindrome (34722743).

The spelling of 22011721 in words is "twenty-two million, eleven thousand, seven hundred twenty-one".