21393958 has 8 divisors (see below), whose sum is σ = 32115600. Its totient is φ = 10688760.

The previous prime is 21393949. The next prime is 21393959. The reversal of 21393958 is 85939312.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21393958.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21393959) by changing a digit.

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, 58 + ... + 6541.

It is an arithmetic number, because the mean of its divisors is an integer number (4014450).

Almost surely, 2^21393958 is an apocalyptic number.

21393958 is a deficient number, since it is larger than the sum of its proper divisors (10721642).

21393958 is a wasteful number, since it uses less digits than its factorization.

21393958 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8222.

The product of its digits is 58320, while the sum is 40.

The square root of 21393958 is about 4625.3603102894. The cubic root of 21393958 is about 277.6069787464.

The spelling of 21393958 in words is "twenty-one million, three hundred ninety-three thousand, nine hundred fifty-eight".