21401121 has 16 divisors (see below), whose sum is σ = 33306624. Its totient is φ = 11968464.

The previous prime is 21401119. The next prime is 21401123. The reversal of 21401121 is 12110412.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21401119) and next prime (21401123).

It is not a de Polignac number, because 21401121 - 2¹ = 21401119 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21401097 and 21401106.

It is not an unprimeable number, because it can be changed into a prime (21401123) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9855 + ... + 11828.

It is an arithmetic number, because the mean of its divisors is an integer number (2081664).

Almost surely, 2^21401121 is an apocalyptic number.

21401121 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21401121 is a deficient number, since it is larger than the sum of its proper divisors (11905503).

21401121 is a wasteful number, since it uses less digits than its factorization.

21401121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21740.

The product of its (nonzero) digits is 16, while the sum is 12.

The square root of 21401121 is about 4626.1345635422. The cubic root of 21401121 is about 277.6379575381.

Adding to 21401121 its reverse (12110412), we get a palindrome (33511533).

The spelling of 21401121 in words is "twenty-one million, four hundred one thousand, one hundred twenty-one".