21342091 has 8 divisors (see below), whose sum is σ = 22476960. Its totient is φ = 20224512.

The previous prime is 21342071. The next prime is 21342119. The reversal of 21342091 is 19024312.

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 21342091 - 2⁵ = 21342059 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21342001) 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 7 ways as a sum of consecutive naturals, for example, 1750 + ... + 6763.

It is an arithmetic number, because the mean of its divisors is an integer number (2809620).

Almost surely, 2^21342091 is an apocalyptic number.

21342091 is a deficient number, since it is larger than the sum of its proper divisors (1134869).

21342091 is a wasteful number, since it uses less digits than its factorization.

21342091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8645.

The product of its (nonzero) digits is 432, while the sum is 22.

The square root of 21342091 is about 4619.7501014665. The cubic root of 21342091 is about 277.3824559665.

It can be divided in two parts, 2134 and 2091, that added together give a square (4225 = 65²).

The spelling of 21342091 in words is "twenty-one million, three hundred forty-two thousand, ninety-one".