8261721069 has 32 divisors (see below), whose sum is σ = 12666264576. Its totient is φ = 4692193920.

The previous prime is 8261721067. The next prime is 8261721079. The reversal of 8261721069 is 9601271628.

It is not a de Polignac number, because 8261721069 - 2¹ = 8261721067 is a prime.

It is a super-2 number, since 2×8261721069² (a number of 21 digits) contains 22 as substring.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 8261721069.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8261721067) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3864969 + ... + 3867105.

It is an arithmetic number, because the mean of its divisors is an integer number (395820768).

Almost surely, 2^8261721069 is an apocalyptic number.

It is an amenable number.

8261721069 is a deficient number, since it is larger than the sum of its proper divisors (4404543507).

8261721069 is a wasteful number, since it uses less digits than its factorization.

8261721069 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3185.

The product of its (nonzero) digits is 72576, while the sum is 42.

The square root of 8261721069 is about 90894.0100831732. The cubic root of 8261721069 is about 2021.5764797760.

The spelling of 8261721069 in words is "eight billion, two hundred sixty-one million, seven hundred twenty-one thousand, sixty-nine".