78722131 has 4 divisors (see below), whose sum is σ = 78751000. Its totient is φ = 78693264.

The previous prime is 78722129. The next prime is 78722141. The reversal of 78722131 is 13122787.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13122787 = 19 ⋅690673.

It is a cyclic number.

It is not a de Polignac number, because 78722131 - 2¹ = 78722129 is a prime.

It is a super-2 number, since 2×78722131² = 12394347818362322, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 78722093 and 78722102.

It is not an unprimeable number, because it can be changed into a prime (78722101) 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, 9861 + ... + 15958.

It is an arithmetic number, because the mean of its divisors is an integer number (19687750).

Almost surely, 2^78722131 is an apocalyptic number.

78722131 is a deficient number, since it is larger than the sum of its proper divisors (28869).

78722131 is a wasteful number, since it uses less digits than its factorization.

78722131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28868.

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

The square root of 78722131 is about 8872.5492954393. The cubic root of 78722131 is about 428.5803751201.

The spelling of 78722131 in words is "seventy-eight million, seven hundred twenty-two thousand, one hundred thirty-one".