72821721026 has 16 divisors (see below), whose sum is σ = 109942932984. Its totient is φ = 36174138624.

The previous prime is 72821721001. The next prime is 72821721047. The reversal of 72821721026 is 62012712827.

It is a Cunningham number, because it is equal to 269855²+1.

It can be written as a sum of positive squares in 4 ways, for example, as 72821721025 + 1 = 269855^2 + 1^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4102346 + ... + 4120058.

Almost surely, 2^72821721026 is an apocalyptic number.

72821721026 is a deficient number, since it is larger than the sum of its proper divisors (37121211958).

72821721026 is a wasteful number, since it uses less digits than its factorization.

72821721026 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30965.

The product of its (nonzero) digits is 37632, while the sum is 38.

The spelling of 72821721026 in words is "seventy-two billion, eight hundred twenty-one million, seven hundred twenty-one thousand, twenty-six".