21106572 has 24 divisors (see below), whose sum is σ = 50297856. Its totient is φ = 6885648.

The previous prime is 21106543. The next prime is 21106573. The reversal of 21106572 is 27560112.

It is not an unprimeable number, because it can be changed into a prime (21106573) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18148 + ... + 19275.

It is an arithmetic number, because the mean of its divisors is an integer number (2095744).

Almost surely, 2^21106572 is an apocalyptic number.

It is an amenable number.

21106572 is an abundant number, since it is smaller than the sum of its proper divisors (29191284).

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

21106572 is a wasteful number, since it uses less digits than its factorization.

21106572 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37477 (or 37475 counting only the distinct ones).

The product of its (nonzero) digits is 840, while the sum is 24.

The square root of 21106572 is about 4594.1889382131. The cubic root of 21106572 is about 276.3583352384.

Adding to 21106572 its reverse (27560112), we get a palindrome (48666684).

The spelling of 21106572 in words is "twenty-one million, one hundred six thousand, five hundred seventy-two".