21293942 has 4 divisors (see below), whose sum is σ = 31940916. Its totient is φ = 10646970.

The previous prime is 21293939. The next prime is 21293947. The reversal of 21293942 is 24939212.

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

It is a junction number, because it is equal to n+sod(n) for n = 21293899 and 21293908.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21293947) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5323484 + ... + 5323487.

It is an arithmetic number, because the mean of its divisors is an integer number (7985229).

Almost surely, 2^21293942 is an apocalyptic number.

21293942 is a deficient number, since it is larger than the sum of its proper divisors (10646974).

21293942 is a wasteful number, since it uses less digits than its factorization.

21293942 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10646973.

The product of its digits is 7776, while the sum is 32.

The square root of 21293942 is about 4614.5359463331. The cubic root of 21293942 is about 277.1737019099.

The spelling of 21293942 in words is "twenty-one million, two hundred ninety-three thousand, nine hundred forty-two".