72196781 has 8 divisors (see below), whose sum is σ = 73335480. Its totient is φ = 71062272.

The previous prime is 72196771. The next prime is 72196801. The reversal of 72196781 is 18769127.

It can be written as a sum of positive squares in 4 ways, for example, as 14891881 + 57304900 = 3859^2 + 7570^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 72196781 - 2¹⁴ = 72180397 is a prime.

It is a super-2 number, since 2×72196781² = 10424750373523922, 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 (72196771) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 59921 + ... + 61113.

It is an arithmetic number, because the mean of its divisors is an integer number (9166935).

Almost surely, 2^72196781 is an apocalyptic number.

It is an amenable number.

72196781 is a deficient number, since it is larger than the sum of its proper divisors (1138699).

72196781 is a wasteful number, since it uses less digits than its factorization.

72196781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2095.

The product of its digits is 42336, while the sum is 41.

The square root of 72196781 is about 8496.8688938926. The cubic root of 72196781 is about 416.3954207577.

The spelling of 72196781 in words is "seventy-two million, one hundred ninety-six thousand, seven hundred eighty-one".