21871536 has 40 divisors (see below), whose sum is σ = 57466560. Its totient is φ = 7166016.

The previous prime is 21871529. The next prime is 21871541. The reversal of 21871536 is 63517812.

It is a junction number, because it is equal to n+sod(n) for n = 21871497 and 21871506.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1030 + ... + 6693.

It is an arithmetic number, because the mean of its divisors is an integer number (1436664).

Almost surely, 2^21871536 is an apocalyptic number.

It is an amenable number.

21871536 is an abundant number, since it is smaller than the sum of its proper divisors (35595024).

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

21871536 is a wasteful number, since it uses less digits than its factorization.

21871536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7793 (or 7787 counting only the distinct ones).

The product of its digits is 10080, while the sum is 33.

The square root of 21871536 is about 4676.7014016291. The cubic root of 21871536 is about 279.6574723087.

The spelling of 21871536 in words is "twenty-one million, eight hundred seventy-one thousand, five hundred thirty-six".