21053798 has 4 divisors (see below), whose sum is σ = 31580700. Its totient is φ = 10526898.

The previous prime is 21053783. The next prime is 21053831. The reversal of 21053798 is 89735012.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5263448 + ... + 5263451.

It is an arithmetic number, because the mean of its divisors is an integer number (7895175).

Almost surely, 2^21053798 is an apocalyptic number.

21053798 is a deficient number, since it is larger than the sum of its proper divisors (10526902).

21053798 is a wasteful number, since it uses less digits than its factorization.

21053798 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10526901.

The product of its (nonzero) digits is 15120, while the sum is 35.

The square root of 21053798 is about 4588.4417834380. The cubic root of 21053798 is about 276.1278113488.

The spelling of 21053798 in words is "twenty-one million, fifty-three thousand, seven hundred ninety-eight".