77978282 has 4 divisors (see below), whose sum is σ = 116967426. Its totient is φ = 38989140.

The previous prime is 77978281. The next prime is 77978323. The reversal of 77978282 is 28287977.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 28287977 = 83 ⋅340819.

It can be written as a sum of positive squares in only one way, i.e., 66896041 + 11082241 = 8179^2 + 3329^2 .

It is a super-2 number, since 2×77978282² = 12161224927343048, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 77978282.

It is not an unprimeable number, because it can be changed into a prime (77978281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19494569 + ... + 19494572.

Almost surely, 2^77978282 is an apocalyptic number.

77978282 is a deficient number, since it is larger than the sum of its proper divisors (38989144).

77978282 is a wasteful number, since it uses less digits than its factorization.

77978282 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38989143.

The product of its digits is 790272, while the sum is 50.

The square root of 77978282 is about 8830.5312410976. The cubic root of 77978282 is about 427.2262091036.

The spelling of 77978282 in words is "seventy-seven million, nine hundred seventy-eight thousand, two hundred eighty-two".