21395798 has 4 divisors (see below), whose sum is σ = 32093700. Its totient is φ = 10697898.

The previous prime is 21395791. The next prime is 21395821. The reversal of 21395798 is 89759312.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21395791) 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, 5348948 + ... + 5348951.

It is an arithmetic number, because the mean of its divisors is an integer number (8023425).

Almost surely, 2^21395798 is an apocalyptic number.

21395798 is a deficient number, since it is larger than the sum of its proper divisors (10697902).

21395798 is a wasteful number, since it uses less digits than its factorization.

21395798 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10697901.

The product of its digits is 136080, while the sum is 44.

The square root of 21395798 is about 4625.5592094362. The cubic root of 21395798 is about 277.6149371023.

The spelling of 21395798 in words is "twenty-one million, three hundred ninety-five thousand, seven hundred ninety-eight".