72781811 has 4 divisors (see below), whose sum is σ = 77063112. Its totient is φ = 68500512.

The previous prime is 72781783. The next prime is 72781829. The reversal of 72781811 is 11818727.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 72781811 - 2⁶ = 72781747 is a prime.

It is a Duffinian number.

It is a zygodrome in base 6.

It is not an unprimeable number, because it can be changed into a prime (72781861) 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, 2140625 + ... + 2140658.

It is an arithmetic number, because the mean of its divisors is an integer number (19265778).

Almost surely, 2^72781811 is an apocalyptic number.

72781811 is a deficient number, since it is larger than the sum of its proper divisors (4281301).

72781811 is a wasteful number, since it uses less digits than its factorization.

72781811 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4281300.

The product of its digits is 6272, while the sum is 35.

The square root of 72781811 is about 8531.2256446539. The cubic root of 72781811 is about 417.5171178754.

The spelling of 72781811 in words is "seventy-two million, seven hundred eighty-one thousand, eight hundred eleven".