8261721064 has 64 divisors (see below), whose sum is σ = 16986594240. Its totient is φ = 3751480320.

The previous prime is 8261721029. The next prime is 8261721067. The reversal of 8261721064 is 4601271628.

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 15 ways as a sum of consecutive naturals, for example, 476874 + ... + 493894.

It is an arithmetic number, because the mean of its divisors is an integer number (265415535).

Almost surely, 2^8261721064 is an apocalyptic number.

It is an amenable number.

8261721064 is an abundant number, since it is smaller than the sum of its proper divisors (8724873176).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

8261721064 is a wasteful number, since it uses less digits than its factorization.

8261721064 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17170 (or 17166 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 37.

The square root of 8261721064 is about 90894.0100556687. The cubic root of 8261721064 is about 2021.5764793682.

The spelling of 8261721064 in words is "eight billion, two hundred sixty-one million, seven hundred twenty-one thousand, sixty-four".