72201661 has 16 divisors (see below), whose sum is σ = 83865600. Its totient is φ = 60884208.

The previous prime is 72201643. The next prime is 72201667. The reversal of 72201661 is 16610227.

It is not a de Polignac number, because 72201661 - 2¹¹ = 72199613 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72201667) 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, 172110 + ... + 172528.

It is an arithmetic number, because the mean of its divisors is an integer number (5241600).

Almost surely, 2^72201661 is an apocalyptic number.

It is an amenable number.

72201661 is a deficient number, since it is larger than the sum of its proper divisors (11663939).

72201661 is a wasteful number, since it uses less digits than its factorization.

72201661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 768.

The product of its (nonzero) digits is 1008, while the sum is 25.

The square root of 72201661 is about 8497.1560536452. The cubic root of 72201661 is about 416.4048023573.

Adding to 72201661 its reverse (16610227), we get a palindrome (88811888).

The spelling of 72201661 in words is "seventy-two million, two hundred one thousand, six hundred sixty-one".