21471836 has 12 divisors (see below), whose sum is σ = 37723728. Its totient is φ = 10693632.

The previous prime is 21471787. The next prime is 21471839. The reversal of 21471836 is 63817412.

It is a super-2 number, since 2×21471836² = 922079482421792, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21471839) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9416 + ... + 11471.

It is an arithmetic number, because the mean of its divisors is an integer number (3143644).

Almost surely, 2^21471836 is an apocalyptic number.

It is an amenable number.

21471836 is a deficient number, since it is larger than the sum of its proper divisors (16251892).

21471836 is a wasteful number, since it uses less digits than its factorization.

21471836 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21148 (or 21146 counting only the distinct ones).

The product of its digits is 8064, while the sum is 32.

The square root of 21471836 is about 4633.7712502885. The cubic root of 21471836 is about 277.9434179136.

The spelling of 21471836 in words is "twenty-one million, four hundred seventy-one thousand, eight hundred thirty-six".