15621442 has 4 divisors (see below), whose sum is σ = 23432166. Its totient is φ = 7810720.

The previous prime is 15621433. The next prime is 15621449. The reversal of 15621442 is 24412651.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 24412651 = 3761 ⋅6491.

It can be written as a sum of positive squares in only one way, i.e., 12666481 + 2954961 = 3559^2 + 1719^2 .

It is not an unprimeable number, because it can be changed into a prime (15621449) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3905359 + ... + 3905362.

Almost surely, 2^15621442 is an apocalyptic number.

15621442 is a deficient number, since it is larger than the sum of its proper divisors (7810724).

15621442 is an equidigital number, since it uses as much as digits as its factorization.

15621442 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7810723.

The product of its digits is 1920, while the sum is 25.

The square root of 15621442 is about 3952.3969942302. The cubic root of 15621442 is about 249.9810225595.

The spelling of 15621442 in words is "fifteen million, six hundred twenty-one thousand, four hundred forty-two".