21401265 has 8 divisors (see below), whose sum is σ = 34242048. Its totient is φ = 11414000.

The previous prime is 21401257. The next prime is 21401269. The reversal of 21401265 is 56210412.

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

It is not a de Polignac number, because 21401265 - 2³ = 21401257 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21401269) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 713361 + ... + 713390.

It is an arithmetic number, because the mean of its divisors is an integer number (4280256).

Almost surely, 2^21401265 is an apocalyptic number.

It is an amenable number.

21401265 is a deficient number, since it is larger than the sum of its proper divisors (12840783).

21401265 is a wasteful number, since it uses less digits than its factorization.

21401265 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1426759.

The product of its (nonzero) digits is 480, while the sum is 21.

The square root of 21401265 is about 4626.1501272657. The cubic root of 21401265 is about 277.6385802434.

Adding to 21401265 its reverse (56210412), we get a palindrome (77611677).

The spelling of 21401265 in words is "twenty-one million, four hundred one thousand, two hundred sixty-five".