21347042 has 4 divisors (see below), whose sum is σ = 32020566. Its totient is φ = 10673520.

The previous prime is 21347041. The next prime is 21347047. The reversal of 21347042 is 24074312.

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., 21335161 + 11881 = 4619^2 + 109^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21346999 and 21347017.

It is not an unprimeable number, because it can be changed into a prime (21347041) 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 as a sum of consecutive naturals, namely, 5336759 + ... + 5336762.

Almost surely, 2^21347042 is an apocalyptic number.

21347042 is a deficient number, since it is larger than the sum of its proper divisors (10673524).

21347042 is a wasteful number, since it uses less digits than its factorization.

21347042 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10673523.

The product of its (nonzero) digits is 1344, while the sum is 23.

The square root of 21347042 is about 4620.2859218884. The cubic root of 21347042 is about 277.4039036362.

The spelling of 21347042 in words is "twenty-one million, three hundred forty-seven thousand, forty-two".