21427401 has 8 divisors (see below), whose sum is σ = 28698880. Its totient is φ = 14220432.

The previous prime is 21427381. The next prime is 21427447. The reversal of 21427401 is 10472412.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21427401 - 2⁵ = 21427369 is a prime.

It is a super-2 number, since 2×21427401² = 918267027229602, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21427451) 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 7 ways as a sum of consecutive naturals, for example, 15346 + ... + 16683.

It is an arithmetic number, because the mean of its divisors is an integer number (3587360).

Almost surely, 2^21427401 is an apocalyptic number.

It is an amenable number.

21427401 is a deficient number, since it is larger than the sum of its proper divisors (7271479).

21427401 is a wasteful number, since it uses less digits than its factorization.

21427401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32255.

The product of its (nonzero) digits is 448, while the sum is 21.

The square root of 21427401 is about 4628.9740764018. The cubic root of 21427401 is about 277.7515550298.

Adding to 21427401 its reverse (10472412), we get a palindrome (31899813).

The spelling of 21427401 in words is "twenty-one million, four hundred twenty-seven thousand, four hundred one".