72781078 has 4 divisors (see below), whose sum is σ = 109171620. Its totient is φ = 36390538.

The previous prime is 72781067. The next prime is 72781103. The reversal of 72781078 is 87018727.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 87018727 = 19 ⋅4579933.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an alternating number because its digits alternate between odd and even.

It is a self number, because there is not a number n which added to its sum of digits gives 72781078.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 18195268 + ... + 18195271.

It is an arithmetic number, because the mean of its divisors is an integer number (27292905).

Almost surely, 2^72781078 is an apocalyptic number.

72781078 is a deficient number, since it is larger than the sum of its proper divisors (36390542).

72781078 is a wasteful number, since it uses less digits than its factorization.

72781078 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36390541.

The product of its (nonzero) digits is 43904, while the sum is 40.

The square root of 72781078 is about 8531.1826847161. The cubic root of 72781078 is about 417.5157162382.

The spelling of 72781078 in words is "seventy-two million, seven hundred eighty-one thousand, seventy-eight".