21702151 has 4 divisors (see below), whose sum is σ = 21832272. Its totient is φ = 21572032.

The previous prime is 21702103. The next prime is 21702157. The reversal of 21702151 is 15120712.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21702151 - 2¹¹ = 21700103 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 (21702157) 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 3 ways as a sum of consecutive naturals, for example, 64810 + ... + 65143.

It is an arithmetic number, because the mean of its divisors is an integer number (5458068).

Almost surely, 2^21702151 is an apocalyptic number.

21702151 is a deficient number, since it is larger than the sum of its proper divisors (130121).

21702151 is a wasteful number, since it uses less digits than its factorization.

21702151 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 130120.

The product of its (nonzero) digits is 140, while the sum is 19.

The square root of 21702151 is about 4658.5567507545. The cubic root of 21702151 is about 278.9336609960.

Adding to 21702151 its reverse (15120712), we get a palindrome (36822863).

The spelling of 21702151 in words is "twenty-one million, seven hundred two thousand, one hundred fifty-one".