21873151 has 4 divisors (see below), whose sum is σ = 21906904. Its totient is φ = 21839400.

The previous prime is 21873149. The next prime is 21873167. The reversal of 21873151 is 15137812.

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 21873151 - 2¹ = 21873149 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 (21873121) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15885 + ... + 17206.

It is an arithmetic number, because the mean of its divisors is an integer number (5476726).

Almost surely, 2^21873151 is an apocalyptic number.

21873151 is a deficient number, since it is larger than the sum of its proper divisors (33753).

21873151 is an equidigital number, since it uses as much as digits as its factorization.

21873151 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33752.

The product of its digits is 1680, while the sum is 28.

The square root of 21873151 is about 4676.8740628758. The cubic root of 21873151 is about 279.6643554665.

The spelling of 21873151 in words is "twenty-one million, eight hundred seventy-three thousand, one hundred fifty-one".