15721401 has 8 divisors (see below), whose sum is σ = 21072384. Its totient is φ = 10425680.

The previous prime is 15721373. The next prime is 15721421. The reversal of 15721401 is 10412751.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 15721401 - 2⁵ = 15721369 is a prime.

It is not an unprimeable number, because it can be changed into a prime (15721421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13146 + ... + 14291.

It is an arithmetic number, because the mean of its divisors is an integer number (2634048).

Almost surely, 2^15721401 is an apocalyptic number.

It is an amenable number.

15721401 is a deficient number, since it is larger than the sum of its proper divisors (5350983).

15721401 is a wasteful number, since it uses less digits than its factorization.

15721401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27631.

The product of its (nonzero) digits is 280, while the sum is 21.

The square root of 15721401 is about 3965.0221941371. The cubic root of 15721401 is about 250.5130849217.

The spelling of 15721401 in words is "fifteen million, seven hundred twenty-one thousand, four hundred one".