21401244 has 36 divisors (see below), whose sum is σ = 55563144. Its totient is φ = 6940512.

The previous prime is 21401203. The next prime is 21401251. The reversal of 21401244 is 44210412.

21401244 is a `hidden beast` number, since 21 + 401 + 244 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6702 + ... + 9365.

Almost surely, 2^21401244 is an apocalyptic number.

It is an amenable number.

21401244 is an abundant number, since it is smaller than the sum of its proper divisors (34161900).

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

21401244 is a wasteful number, since it uses less digits than its factorization.

21401244 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16114 (or 16109 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 18.

The square root of 21401244 is about 4626.1478575592. The cubic root of 21401244 is about 277.6384894324.

Adding to 21401244 its reverse (44210412), we get a palindrome (65611656).

The spelling of 21401244 in words is "twenty-one million, four hundred one thousand, two hundred forty-four".