21427601 has 4 divisors (see below), whose sum is σ = 23075892. Its totient is φ = 19779312.

The previous prime is 21427583. The next prime is 21427613. The reversal of 21427601 is 10672412.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2496400 + 18931201 = 1580^2 + 4351^2 .

It is a cyclic number.

It is not a de Polignac number, because 21427601 - 2⁶ = 21427537 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21427621) 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 3 ways as a sum of consecutive naturals, for example, 824126 + ... + 824151.

It is an arithmetic number, because the mean of its divisors is an integer number (5768973).

Almost surely, 2^21427601 is an apocalyptic number.

It is an amenable number.

21427601 is a deficient number, since it is larger than the sum of its proper divisors (1648291).

21427601 is a wasteful number, since it uses less digits than its factorization.

21427601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1648290.

The product of its (nonzero) digits is 672, while the sum is 23.

The square root of 21427601 is about 4628.9956794104. The cubic root of 21427601 is about 277.7524191902.

The spelling of 21427601 in words is "twenty-one million, four hundred twenty-seven thousand, six hundred one".