21028958 has 4 divisors (see below), whose sum is σ = 31543440. Its totient is φ = 10514478.

The previous prime is 21028939. The next prime is 21028979. The reversal of 21028958 is 85982012.

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, 5257238 + ... + 5257241.

It is an arithmetic number, because the mean of its divisors is an integer number (7885860).

Almost surely, 2^21028958 is an apocalyptic number.

21028958 is a deficient number, since it is larger than the sum of its proper divisors (10514482).

21028958 is a wasteful number, since it uses less digits than its factorization.

21028958 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10514481.

The product of its (nonzero) digits is 11520, while the sum is 35.

The square root of 21028958 is about 4585.7341833124. The cubic root of 21028958 is about 276.0191735612.

The spelling of 21028958 in words is "twenty-one million, twenty-eight thousand, nine hundred fifty-eight".