21072342 has 8 divisors (see below), whose sum is σ = 42144696. Its totient is φ = 7024112.

The previous prime is 21072329. The next prime is 21072361. The reversal of 21072342 is 24327012.

It is a sphenic number, since it is the product of 3 distinct primes.

21072342 is an admirable number.

It is a congruent number.

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 in 3 ways as a sum of consecutive naturals, for example, 1756023 + ... + 1756034.

It is an arithmetic number, because the mean of its divisors is an integer number (5268087).

Almost surely, 2^21072342 is an apocalyptic number.

21072342 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21072342 is a wasteful number, since it uses less digits than its factorization.

21072342 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3512062.

The product of its (nonzero) digits is 672, while the sum is 21.

The square root of 21072342 is about 4590.4620682454. The cubic root of 21072342 is about 276.2088578738.

Adding to 21072342 its reverse (24327012), we get a palindrome (45399354).

The spelling of 21072342 in words is "twenty-one million, seventy-two thousand, three hundred forty-two".