72726781 has 2 divisors, whose sum is σ = 72726782. Its totient is φ = 72726780.

The previous prime is 72726769. The next prime is 72726821. The reversal of 72726781 is 18762727.

It is an a-pointer prime, because the next prime (72726821) can be obtained adding 72726781 to its sum of digits (40).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 50552100 + 22174681 = 7110^2 + 4709^2 .

It is an emirp because it is prime and its reverse (18762727) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 72726781 - 2¹¹ = 72724733 is a prime.

It is a super-2 number, since 2×72726781² = 10578369349243922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (72726481) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36363390 + 36363391.

It is an arithmetic number, because the mean of its divisors is an integer number (36363391).

Almost surely, 2^72726781 is an apocalyptic number.

It is an amenable number.

72726781 is a deficient number, since it is larger than the sum of its proper divisors (1).

72726781 is an equidigital number, since it uses as much as digits as its factorization.

72726781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 65856, while the sum is 40.

The square root of 72726781 is about 8527.9998241088. Note that the first 3 decimals coincide. The cubic root of 72726781 is about 417.4118637384.

The spelling of 72726781 in words is "seventy-two million, seven hundred twenty-six thousand, seven hundred eighty-one".