21571892 has 6 divisors (see below), whose sum is σ = 37750818. Its totient is φ = 10785944.

The previous prime is 21571867. The next prime is 21571903. The reversal of 21571892 is 29817512.

It can be written as a sum of positive squares in only one way, i.e., 15792676 + 5779216 = 3974^2 + 2404^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2696483 + ... + 2696490.

It is an arithmetic number, because the mean of its divisors is an integer number (6291803).

Almost surely, 2^21571892 is an apocalyptic number.

It is an amenable number.

21571892 is a deficient number, since it is larger than the sum of its proper divisors (16178926).

21571892 is a wasteful number, since it uses less digits than its factorization.

21571892 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5392977 (or 5392975 counting only the distinct ones).

The product of its digits is 10080, while the sum is 35.

The square root of 21571892 is about 4644.5550917176. Note that the first 3 decimals coincide. The cubic root of 21571892 is about 278.3744759321.

The spelling of 21571892 in words is "twenty-one million, five hundred seventy-one thousand, eight hundred ninety-two".