221764731 has 8 divisors (see below), whose sum is σ = 305224704. Its totient is φ = 143073960.

The previous prime is 221764727. The next prime is 221764747. The reversal of 221764731 is 137467122.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 221764731 - 2² = 221764727 is a prime.

It is a super-2 number, since 2×221764731² = 98359191831004722, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 221764692 and 221764701.

It is not an unprimeable number, because it can be changed into a prime (221764831) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1192191 + ... + 1192376.

It is an arithmetic number, because the mean of its divisors is an integer number (38153088).

Almost surely, 2^221764731 is an apocalyptic number.

221764731 is a deficient number, since it is larger than the sum of its proper divisors (83459973).

221764731 is a wasteful number, since it uses less digits than its factorization.

221764731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2384601.

The product of its digits is 14112, while the sum is 33.

The square root of 221764731 is about 14891.7672221936. The cubic root of 221764731 is about 605.2909203501.

The spelling of 221764731 in words is "two hundred twenty-one million, seven hundred sixty-four thousand, seven hundred thirty-one".