772749221 has 4 divisors (see below), whose sum is σ = 774976512. Its totient is φ = 770521932.

The previous prime is 772749203. The next prime is 772749223. The reversal of 772749221 is 122947277.

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.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-772749221 is a prime.

It is a super-3 number, since 3×772749221³ (a number of 28 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (772749223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1113125 + ... + 1113818.

It is an arithmetic number, because the mean of its divisors is an integer number (193744128).

Almost surely, 2^772749221 is an apocalyptic number.

It is an amenable number.

772749221 is a deficient number, since it is larger than the sum of its proper divisors (2227291).

772749221 is a wasteful number, since it uses less digits than its factorization.

772749221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2227290.

The product of its digits is 98784, while the sum is 41.

The square root of 772749221 is about 27798.3672362245. The cubic root of 772749221 is about 917.6551902353.

The spelling of 772749221 in words is "seven hundred seventy-two million, seven hundred forty-nine thousand, two hundred twenty-one".