21571534416 has 20 divisors (see below), whose sum is σ = 55726464032. Its totient is φ = 7190511456.

The previous prime is 21571534403. The next prime is 21571534427. The reversal of 21571534416 is 61443517512.

It is a super-2 number, since 2×21571534416² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 224703436 + ... + 224703531.

Almost surely, 2^21571534416 is an apocalyptic number.

It is an amenable number.

21571534416 is an abundant number, since it is smaller than the sum of its proper divisors (34154929616).

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

21571534416 is a wasteful number, since it uses less digits than its factorization.

21571534416 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 449406978 (or 449406972 counting only the distinct ones).

The product of its digits is 100800, while the sum is 39.

The spelling of 21571534416 in words is "twenty-one billion, five hundred seventy-one million, five hundred thirty-four thousand, four hundred sixteen".