22019981 has 4 divisors (see below), whose sum is σ = 23315292. Its totient is φ = 20724672.

The previous prime is 22019969. The next prime is 22019989. The reversal of 22019981 is 18991022.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 18139081 + 3880900 = 4259^2 + 1970^2 .

It is a cyclic number.

It is not a de Polignac number, because 22019981 - 2¹⁸ = 21757837 is a prime.

It is a super-2 number, since 2×22019981² = 969759126480722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (22019989) 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, 647630 + ... + 647663.

It is an arithmetic number, because the mean of its divisors is an integer number (5828823).

Almost surely, 2^22019981 is an apocalyptic number.

It is an amenable number.

22019981 is a deficient number, since it is larger than the sum of its proper divisors (1295311).

22019981 is a wasteful number, since it uses less digits than its factorization.

22019981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1295310.

The product of its (nonzero) digits is 2592, while the sum is 32.

The square root of 22019981 is about 4692.5452581728. The cubic root of 22019981 is about 280.2887370149.

The spelling of 22019981 in words is "twenty-two million, nineteen thousand, nine hundred eighty-one".