21404151 has 12 divisors (see below), whose sum is σ = 30974320. Its totient is φ = 14243040.

The previous prime is 21404147. The next prime is 21404183. The reversal of 21404151 is 15140412.

It is not a de Polignac number, because 21404151 - 2² = 21404147 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21404101) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3795 + ... + 7563.

Almost surely, 2^21404151 is an apocalyptic number.

21404151 is a deficient number, since it is larger than the sum of its proper divisors (9570169).

21404151 is a wasteful number, since it uses less digits than its factorization.

21404151 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4406 (or 4403 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 18.

The square root of 21404151 is about 4626.4620391829. The cubic root of 21404151 is about 277.6510597071.

Adding to 21404151 its reverse (15140412), we get a palindrome (36544563).

The spelling of 21404151 in words is "twenty-one million, four hundred four thousand, one hundred fifty-one".