21571672 has 8 divisors (see below), whose sum is σ = 40446900. Its totient is φ = 10785832.

The previous prime is 21571651. The next prime is 21571673. The reversal of 21571672 is 27617512.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21571673) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1348222 + ... + 1348237.

Almost surely, 2^21571672 is an apocalyptic number.

It is an amenable number.

21571672 is a deficient number, since it is larger than the sum of its proper divisors (18875228).

21571672 is a wasteful number, since it uses less digits than its factorization.

21571672 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2696465 (or 2696461 counting only the distinct ones).

The product of its digits is 5880, while the sum is 31.

The square root of 21571672 is about 4644.5314080109. The cubic root of 21571672 is about 278.3735295989.

The spelling of 21571672 in words is "twenty-one million, five hundred seventy-one thousand, six hundred seventy-two".