22197981 has 12 divisors (see below), whose sum is σ = 32049888. Its totient is φ = 13659984.

The previous prime is 22197979. The next prime is 22197991. The reversal of 22197981 is 18979122.

22197981 = 184² + 185² + ... + 417².

It is not a de Polignac number, because 22197981 - 2¹ = 22197979 is a prime.

It is a super-2 number, since 2×22197981² = 985500720952722, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (22197941) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 21385 + ... + 22398.

It is an arithmetic number, because the mean of its divisors is an integer number (2670824).

Almost surely, 2^22197981 is an apocalyptic number.

It is an amenable number.

22197981 is a deficient number, since it is larger than the sum of its proper divisors (9851907).

22197981 is a wasteful number, since it uses less digits than its factorization.

22197981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43812 (or 43799 counting only the distinct ones).

The product of its digits is 18144, while the sum is 39.

The square root of 22197981 is about 4711.4733364416. The cubic root of 22197981 is about 281.0419553790.

The spelling of 22197981 in words is "twenty-two million, one hundred ninety-seven thousand, nine hundred eighty-one".