78242237581 has 4 divisors (see below), whose sum is σ = 78569611200. Its totient is φ = 77914863964.

The previous prime is 78242237543. The next prime is 78242237611. The reversal of 78242237581 is 18573224287.

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, and also an emirpimes, since its reverse is a distinct semiprime: 18573224287 = 1871 ⋅9926897.

It is a cyclic number.

It is not a de Polignac number, because 78242237581 - 2³³ = 69652302989 is a prime.

It is a super-2 number, since 2×78242237581² (a number of 23 digits) 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 (78242237881) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 163686451 + ... + 163686928.

It is an arithmetic number, because the mean of its divisors is an integer number (19642402800).

Almost surely, 2^78242237581 is an apocalyptic number.

It is an amenable number.

78242237581 is a deficient number, since it is larger than the sum of its proper divisors (327373619).

78242237581 is a wasteful number, since it uses less digits than its factorization.

78242237581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 327373618.

The product of its digits is 1505280, while the sum is 49.

The spelling of 78242237581 in words is "seventy-eight billion, two hundred forty-two million, two hundred thirty-seven thousand, five hundred eighty-one".