21471331 has 16 divisors (see below), whose sum is σ = 25482240. Its totient is φ = 17709120.

The previous prime is 21471301. The next prime is 21471337. The reversal of 21471331 is 13317412.

It is a cyclic number.

It is not a de Polignac number, because 21471331 - 2⁵ = 21471299 is a prime.

It is a super-2 number, since 2×21471331² = 922036109823122, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21471337) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22200 + ... + 23146.

It is an arithmetic number, because the mean of its divisors is an integer number (1592640).

Almost surely, 2^21471331 is an apocalyptic number.

21471331 is a deficient number, since it is larger than the sum of its proper divisors (4010909).

21471331 is an equidigital number, since it uses as much as digits as its factorization.

21471331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1074.

The product of its digits is 504, while the sum is 22.

The square root of 21471331 is about 4633.7167587154. The cubic root of 21471331 is about 277.9412388960.

Adding to 21471331 its reverse (13317412), we get a palindrome (34788743).

The spelling of 21471331 in words is "twenty-one million, four hundred seventy-one thousand, three hundred thirty-one".