21428658 has 32 divisors (see below), whose sum is σ = 48121920. Its totient is φ = 7067520.

The previous prime is 21428621. The next prime is 21428681. The reversal of 21428658 is 85682412.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3193 + ... + 7283.

It is an arithmetic number, because the mean of its divisors is an integer number (1503810).

Almost surely, 2^21428658 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21428658, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24060960).

21428658 is an abundant number, since it is smaller than the sum of its proper divisors (26693262).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21428658 is a wasteful number, since it uses less digits than its factorization.

21428658 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4199 (or 4193 counting only the distinct ones).

The product of its digits is 30720, while the sum is 36.

The square root of 21428658 is about 4629.1098496363. The cubic root of 21428658 is about 277.7569861890.

The spelling of 21428658 in words is "twenty-one million, four hundred twenty-eight thousand, six hundred fifty-eight".