8721601 has 4 divisors (see below), whose sum is σ = 9967552. Its totient is φ = 7475652.

The previous prime is 8721599. The next prime is 8721607. The reversal of 8721601 is 1061278.

8721601 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 8721601 - 2¹ = 8721599 is a prime.

It is not an unprimeable number, because it can be changed into a prime (8721607) 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, 622965 + ... + 622978.

It is an arithmetic number, because the mean of its divisors is an integer number (2491888).

Almost surely, 2^8721601 is an apocalyptic number.

It is an amenable number.

8721601 is a deficient number, since it is larger than the sum of its proper divisors (1245951).

8721601 is a wasteful number, since it uses less digits than its factorization.

8721601 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1245950.

The product of its (nonzero) digits is 672, while the sum is 25.

The square root of 8721601 is about 2953.2356831110. The cubic root of 8721601 is about 205.8410893102.

Subtracting from 8721601 its sum of digits (25), we obtain a triangular number (8721576 = T₄₁₇₆).

Adding to 8721601 its reverse (1061278), we get a palindrome (9782879).

The spelling of 8721601 in words is "eight million, seven hundred twenty-one thousand, six hundred one".