221991736 has 8 divisors (see below), whose sum is σ = 416234520. Its totient is φ = 110995864.

The previous prime is 221991733. The next prime is 221991751. The reversal of 221991736 is 637199122.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221991733) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13874476 + ... + 13874491.

It is an arithmetic number, because the mean of its divisors is an integer number (52029315).

Almost surely, 2^221991736 is an apocalyptic number.

It is an amenable number.

221991736 is a deficient number, since it is larger than the sum of its proper divisors (194242784).

221991736 is a wasteful number, since it uses less digits than its factorization.

221991736 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27748973 (or 27748969 counting only the distinct ones).

The product of its digits is 40824, while the sum is 40.

The square root of 221991736 is about 14899.3871014884. The cubic root of 221991736 is about 605.4973812059.

The spelling of 221991736 in words is "two hundred twenty-one million, nine hundred ninety-one thousand, seven hundred thirty-six".