21020158 has 4 divisors (see below), whose sum is σ = 31530240. Its totient is φ = 10510078.

The previous prime is 21020119. The next prime is 21020159. The reversal of 21020158 is 85102012.

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 (21020159) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5255038 + ... + 5255041.

It is an arithmetic number, because the mean of its divisors is an integer number (7882560).

Almost surely, 2^21020158 is an apocalyptic number.

21020158 is a deficient number, since it is larger than the sum of its proper divisors (10510082).

21020158 is a wasteful number, since it uses less digits than its factorization.

21020158 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10510081.

The product of its (nonzero) digits is 160, while the sum is 19.

The square root of 21020158 is about 4584.7745855167. The cubic root of 21020158 is about 275.9806662225.

The spelling of 21020158 in words is "twenty-one million, twenty thousand, one hundred fifty-eight".