21427650 has 72 divisors (see below), whose sum is σ = 60977124. Its totient is φ = 5376000.

The previous prime is 21427643. The next prime is 21427657. The reversal of 21427650 is 5672412.

21427650 is a `hidden beast` number, since 2 + 1 + 4 + 2 + 7 + 650 = 666.

It is an interprime number because it is at equal distance from previous prime (21427643) and next prime (21427657).

It can be written as a sum of positive squares in 6 ways, for example, as 10949481 + 10478169 = 3309^2 + 3237^2 .

It is not an unprimeable number, because it can be changed into a prime (21427657) 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 in 35 ways as a sum of consecutive naturals, for example, 6250 + ... + 9050.

Almost surely, 2^21427650 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21427650, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30488562).

21427650 is an abundant number, since it is smaller than the sum of its proper divisors (39549474).

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

21427650 is a wasteful number, since it uses less digits than its factorization.

21427650 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2836 (or 2828 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 27.

The square root of 21427650 is about 4629.0009721321. Note that the first 3 decimals coincide. The cubic root of 21427650 is about 277.7526309087.

The spelling of 21427650 in words is "twenty-one million, four hundred twenty-seven thousand, six hundred fifty".