21427641 has 9 divisors (see below), whose sum is σ = 30971109. Its totient is φ = 14275836.

The previous prime is 21427639. The next prime is 21427643. The reversal of 21427641 is 14672412.

The square root of 21427641 is 4629.

It is a perfect power (a square), and thus also a powerful number.

21427641 is a `hidden beast` number, since 2 + 14 + 2 + 7 + 641 = 666.

It is an interprime number because it is at equal distance from previous prime (21427639) and next prime (21427643).

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 21427641 - 2¹ = 21427639 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21427643) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 13116 + ... + 14658.

Almost surely, 2^21427641 is an apocalyptic number.

21427641 is the 4629-th square number.

21427641 is the 2315-th centered octagonal number.

It is an amenable number.

21427641 is a deficient number, since it is larger than the sum of its proper divisors (9543468).

21427641 is an frugal number, since it uses more digits than its factorization.

21427641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3092 (or 1546 counting only the distinct ones).

The product of its digits is 2688, while the sum is 27.

The cubic root of 21427641 is about 277.7525920217.

The spelling of 21427641 in words is "twenty-one million, four hundred twenty-seven thousand, six hundred forty-one".