21059242 has 4 divisors (see below), whose sum is σ = 31588866. Its totient is φ = 10529620.

The previous prime is 21059231. The next prime is 21059251. The reversal of 21059242 is 24295012.

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

It can be written as a sum of positive squares in only one way, i.e., 12538681 + 8520561 = 3541^2 + 2919^2 .

It is a super-2 number, since 2×21059242² = 886983347229128, which contains 22 as substring.

It is a zygodrome in base 4.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 5264809 + ... + 5264812.

Almost surely, 2^21059242 is an apocalyptic number.

21059242 is a deficient number, since it is larger than the sum of its proper divisors (10529624).

21059242 is a wasteful number, since it uses less digits than its factorization.

21059242 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10529623.

The product of its (nonzero) digits is 1440, while the sum is 25.

The square root of 21059242 is about 4589.0349748068. The cubic root of 21059242 is about 276.1516092760.

The spelling of 21059242 in words is "twenty-one million, fifty-nine thousand, two hundred forty-two".