82121377 has 4 divisors (see below), whose sum is σ = 88438420. Its totient is φ = 75804336.

The previous prime is 82121371. The next prime is 82121381. The reversal of 82121377 is 77312128.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 24117921 + 58003456 = 4911^2 + 7616^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-82121377 is a prime.

It is a super-2 number, since 2×82121377² = 13487841120752258, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (82121371) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3158502 + ... + 3158527.

It is an arithmetic number, because the mean of its divisors is an integer number (22109605).

Almost surely, 2^82121377 is an apocalyptic number.

It is an amenable number.

82121377 is a deficient number, since it is larger than the sum of its proper divisors (6317043).

82121377 is a wasteful number, since it uses less digits than its factorization.

82121377 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6317042.

The product of its digits is 4704, while the sum is 31.

The square root of 82121377 is about 9062.0845835823. The cubic root of 82121377 is about 434.6624006752.

Subtracting from 82121377 its reverse (77312128), we obtain a square (4809249 = 2193²).

The spelling of 82121377 in words is "eighty-two million, one hundred twenty-one thousand, three hundred seventy-seven".