21053671 has 6 divisors (see below), whose sum is σ = 22009400. Its totient is φ = 20137788.

The previous prime is 21053663. The next prime is 21053699. The reversal of 21053671 is 17635012.

It is not a de Polignac number, because 21053671 - 2³ = 21053663 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21053651) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 19371 + ... + 20428.

Almost surely, 2^21053671 is an apocalyptic number.

21053671 is a deficient number, since it is larger than the sum of its proper divisors (955729).

21053671 is an equidigital number, since it uses as much as digits as its factorization.

21053671 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39845 (or 39822 counting only the distinct ones).

The product of its (nonzero) digits is 1260, while the sum is 25.

The square root of 21053671 is about 4588.4279442964. The cubic root of 21053671 is about 276.1272561314.

Adding to 21053671 its reverse (17635012), we get a palindrome (38688683).

It can be divided in two parts, 2105 and 3671, that added together give a square (5776 = 76²).

The spelling of 21053671 in words is "twenty-one million, fifty-three thousand, six hundred seventy-one".