21699151 has 4 divisors (see below), whose sum is σ = 21855400. Its totient is φ = 21542904.

The previous prime is 21699149. The next prime is 21699187. The reversal of 21699151 is 15199612.

It is a happy number.

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 21699151 - 2¹ = 21699149 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 (21699751) 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 3 ways as a sum of consecutive naturals, for example, 77916 + ... + 78193.

It is an arithmetic number, because the mean of its divisors is an integer number (5463850).

Almost surely, 2^21699151 is an apocalyptic number.

21699151 is a deficient number, since it is larger than the sum of its proper divisors (156249).

21699151 is a wasteful number, since it uses less digits than its factorization.

21699151 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 156248.

The product of its digits is 4860, while the sum is 34.

The square root of 21699151 is about 4658.2347514912. The cubic root of 21699151 is about 278.9208075920.

The spelling of 21699151 in words is "twenty-one million, six hundred ninety-nine thousand, one hundred fifty-one".