82779621 has 4 divisors (see below), whose sum is σ = 110372832. Its totient is φ = 55186412.

The previous prime is 82779569. The next prime is 82779649. The reversal of 82779621 is 12697728.

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 not a de Polignac number, because 82779621 - 2⁷ = 82779493 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (82779721) 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, 13796601 + ... + 13796606.

It is an arithmetic number, because the mean of its divisors is an integer number (27593208).

Almost surely, 2^82779621 is an apocalyptic number.

It is an amenable number.

82779621 is a deficient number, since it is larger than the sum of its proper divisors (27593211).

82779621 is a wasteful number, since it uses less digits than its factorization.

82779621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27593210.

The product of its digits is 84672, while the sum is 42.

The square root of 82779621 is about 9098.3306710627. The cubic root of 82779621 is about 435.8206571687.

The spelling of 82779621 in words is "eighty-two million, seven hundred seventy-nine thousand, six hundred twenty-one".