22405681 has 2 divisors, whose sum is σ = 22405682. Its totient is φ = 22405680.

The previous prime is 22405679. The next prime is 22405687. The reversal of 22405681 is 18650422.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19219456 + 3186225 = 4384^2 + 1785^2 .

It is a cyclic number.

It is not a de Polignac number, because 22405681 - 2¹ = 22405679 is a prime.

It is a super-2 number, since 2×22405681² = 1004029082147522, which contains 22 as substring.

Together with 22405679, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (22405687) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11202840 + 11202841.

It is an arithmetic number, because the mean of its divisors is an integer number (11202841).

Almost surely, 2^22405681 is an apocalyptic number.

It is an amenable number.

22405681 is a deficient number, since it is larger than the sum of its proper divisors (1).

22405681 is an equidigital number, since it uses as much as digits as its factorization.

22405681 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3840, while the sum is 28.

The square root of 22405681 is about 4733.4639535968. The cubic root of 22405681 is about 281.9157780445.

It can be divided in two parts, 2240 and 5681, that added together give a square (7921 = 89²).

The spelling of 22405681 in words is "twenty-two million, four hundred five thousand, six hundred eighty-one".