82749221 has 4 divisors (see below), whose sum is σ = 83984352. Its totient is φ = 81514092.

The previous prime is 82749197. The next prime is 82749229. The reversal of 82749221 is 12294728.

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-82749221 is a prime.

It is a super-2 number, since 2×82749221² = 13694867152213682, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (82749229) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 617465 + ... + 617598.

It is an arithmetic number, because the mean of its divisors is an integer number (20996088).

Almost surely, 2^82749221 is an apocalyptic number.

It is an amenable number.

82749221 is a deficient number, since it is larger than the sum of its proper divisors (1235131).

82749221 is a wasteful number, since it uses less digits than its factorization.

82749221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1235130.

The product of its digits is 16128, while the sum is 35.

The square root of 82749221 is about 9096.6598815170. The cubic root of 82749221 is about 435.7673003562.

The spelling of 82749221 in words is "eighty-two million, seven hundred forty-nine thousand, two hundred twenty-one".