15221601 has 10 divisors (see below), whose sum is σ = 22738562. Its totient is φ = 10147680.

The previous prime is 15221597. The next prime is 15221617. The reversal of 15221601 is 10612251.

It can be written as a sum of positive squares in only one way, i.e., 10556001 + 4665600 = 3249^2 + 2160^2 .

It is not a de Polignac number, because 15221601 - 2² = 15221597 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (15221501) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 93880 + ... + 94041.

Almost surely, 2^15221601 is an apocalyptic number.

It is an amenable number.

15221601 is a deficient number, since it is larger than the sum of its proper divisors (7516961).

15221601 is an equidigital number, since it uses as much as digits as its factorization.

15221601 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 187933 (or 187924 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 18.

The square root of 15221601 is about 3901.4870241999. The cubic root of 15221601 is about 247.8297533000.

Adding to 15221601 its reverse (10612251), we get a palindrome (25833852).

The spelling of 15221601 in words is "fifteen million, two hundred twenty-one thousand, six hundred one".