21471636 has 48 divisors (see below), whose sum is σ = 51451904. Its totient is φ = 6967296.

The previous prime is 21471631. The next prime is 21471641. The reversal of 21471636 is 63617412.

It is an interprime number because it is at equal distance from previous prime (21471631) and next prime (21471641).

It is a super-2 number, since 2×21471636² = 922062305032992, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21471631) 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, 111156 + ... + 111348.

Almost surely, 2^21471636 is an apocalyptic number.

It is an amenable number.

21471636 is an abundant number, since it is smaller than the sum of its proper divisors (29980268).

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

21471636 is a wasteful number, since it uses less digits than its factorization.

21471636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 400 (or 398 counting only the distinct ones).

The product of its digits is 6048, while the sum is 30.

The square root of 21471636 is about 4633.7496695441. The cubic root of 21471636 is about 277.9425549404.

The spelling of 21471636 in words is "twenty-one million, four hundred seventy-one thousand, six hundred thirty-six".