21401497 has 8 divisors (see below), whose sum is σ = 23538816. Its totient is φ = 19334352.

The previous prime is 21401473. The next prime is 21401531. The reversal of 21401497 is 79410412.

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 21401497 - 2¹⁵ = 21368729 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21401407) 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 in 7 ways as a sum of consecutive naturals, for example, 16903 + ... + 18124.

It is an arithmetic number, because the mean of its divisors is an integer number (2942352).

Almost surely, 2^21401497 is an apocalyptic number.

It is an amenable number.

21401497 is a deficient number, since it is larger than the sum of its proper divisors (2137319).

21401497 is a wasteful number, since it uses less digits than its factorization.

21401497 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35087.

The product of its (nonzero) digits is 2016, while the sum is 28.

The square root of 21401497 is about 4626.1752020433. The cubic root of 21401497 is about 277.6395834850.

The spelling of 21401497 in words is "twenty-one million, four hundred one thousand, four hundred ninety-seven".