221000761 has 4 divisors (see below), whose sum is σ = 232632400. Its totient is φ = 209369124.

The previous prime is 221000749. The next prime is 221000789. The reversal of 221000761 is 167000122.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 167000122 = 2 ⋅83500061.

It is a cyclic number.

It is not a de Polignac number, because 221000761 - 2⁹ = 221000249 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (19), and also a Moran number because the ratio is a prime number: 11631619 = 221000761 / (2 + 2 + 1 + 0 + 0 + 0 + 7 + 6 + 1).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221000861) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5815791 + ... + 5815828.

It is an arithmetic number, because the mean of its divisors is an integer number (58158100).

Almost surely, 2^221000761 is an apocalyptic number.

It is an amenable number.

221000761 is a deficient number, since it is larger than the sum of its proper divisors (11631639).

221000761 is a wasteful number, since it uses less digits than its factorization.

221000761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11631638.

The product of its (nonzero) digits is 168, while the sum is 19.

The square root of 221000761 is about 14866.0943424963. The cubic root of 221000761 is about 604.5950535617.

Adding to 221000761 its reverse (167000122), we get a palindrome (388000883).

The spelling of 221000761 in words is "two hundred twenty-one million, seven hundred sixty-one", and thus it is an aban number.