15421691 has 4 divisors (see below), whose sum is σ = 15483384. Its totient is φ = 15360000.

The previous prime is 15421667. The next prime is 15421709. The reversal of 15421691 is 19612451.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19612451 = 3863 ⋅5077.

It is a cyclic number.

It is not a de Polignac number, because 15421691 - 2²² = 11227387 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (15423691) 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, 30470 + ... + 30971.

It is an arithmetic number, because the mean of its divisors is an integer number (3870846).

Almost surely, 2^15421691 is an apocalyptic number.

15421691 is a deficient number, since it is larger than the sum of its proper divisors (61693).

15421691 is an equidigital number, since it uses as much as digits as its factorization.

15421691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61692.

The product of its digits is 2160, while the sum is 29.

The square root of 15421691 is about 3927.0460908933. The cubic root of 15421691 is about 248.9109480859.

The spelling of 15421691 in words is "fifteen million, four hundred twenty-one thousand, six hundred ninety-one".