72303661 has 4 divisors (see below), whose sum is σ = 74257852. Its totient is φ = 70349472.

The previous prime is 72303643. The next prime is 72303667. The reversal of 72303661 is 16630327.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 16630327 = 7 ⋅2375761.

It can be written as a sum of positive squares in 2 ways, for example, as 42328036 + 29975625 = 6506^2 + 5475^2 .

It is a cyclic number.

It is not a de Polignac number, because 72303661 - 2⁵ = 72303629 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72303667) 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, 977040 + ... + 977113.

It is an arithmetic number, because the mean of its divisors is an integer number (18564463).

Almost surely, 2^72303661 is an apocalyptic number.

It is an amenable number.

72303661 is a deficient number, since it is larger than the sum of its proper divisors (1954191).

72303661 is a wasteful number, since it uses less digits than its factorization.

72303661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1954190.

The product of its (nonzero) digits is 4536, while the sum is 28.

The square root of 72303661 is about 8503.1559435306. The cubic root of 72303661 is about 416.6007964850.

Adding to 72303661 its reverse (16630327), we get a palindrome (88933988).

The spelling of 72303661 in words is "seventy-two million, three hundred three thousand, six hundred sixty-one".