21402151 has 8 divisors (see below), whose sum is σ = 22619520. Its totient is φ = 20193912.

The previous prime is 21402149. The next prime is 21402163. The reversal of 21402151 is 15120412.

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 21402151 - 2¹ = 21402149 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 (21402181) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2856 + ... + 7138.

It is an arithmetic number, because the mean of its divisors is an integer number (2827440).

Almost surely, 2^21402151 is an apocalyptic number.

21402151 is a deficient number, since it is larger than the sum of its proper divisors (1217369).

21402151 is a wasteful number, since it uses less digits than its factorization.

21402151 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4565.

The product of its (nonzero) digits is 80, while the sum is 16.

The square root of 21402151 is about 4626.2458862451. The cubic root of 21402151 is about 277.6424115494.

Adding to 21402151 its reverse (15120412), we get a palindrome (36522563).

The spelling of 21402151 in words is "twenty-one million, four hundred two thousand, one hundred fifty-one".