78283981 has 4 divisors (see below), whose sum is σ = 78310332. Its totient is φ = 78257632.

The previous prime is 78283979. The next prime is 78283993. The reversal of 78283981 is 18938287.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18938287 = 67 ⋅282661.

It can be written as a sum of positive squares in 2 ways, for example, as 49928356 + 28355625 = 7066^2 + 5325^2 .

It is a cyclic number.

It is not a de Polignac number, because 78283981 - 2¹ = 78283979 is a prime.

It is a super-2 number, since 2×78283981² = 12256763362416722, 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 (78283921) 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, 8056 + ... + 14881.

It is an arithmetic number, because the mean of its divisors is an integer number (19577583).

Almost surely, 2^78283981 is an apocalyptic number.

It is an amenable number.

78283981 is a deficient number, since it is larger than the sum of its proper divisors (26351).

78283981 is a wasteful number, since it uses less digits than its factorization.

78283981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26350.

The product of its digits is 193536, while the sum is 46.

The square root of 78283981 is about 8847.8235176794. The cubic root of 78283981 is about 427.7837674592.

The spelling of 78283981 in words is "seventy-eight million, two hundred eighty-three thousand, nine hundred eighty-one".