21071572 has 12 divisors (see below), whose sum is σ = 36923040. Its totient is φ = 10522136.

The previous prime is 21071563. The next prime is 21071579. The reversal of 21071572 is 27517012.

It is a happy number.

It is a super-2 number, since 2×21071572² = 888022293102368, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21071579) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 579 + ... + 6517.

It is an arithmetic number, because the mean of its divisors is an integer number (3076920).

Almost surely, 2^21071572 is an apocalyptic number.

It is an amenable number.

21071572 is a deficient number, since it is larger than the sum of its proper divisors (15851468).

21071572 is a wasteful number, since it uses less digits than its factorization.

21071572 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6830 (or 6828 counting only the distinct ones).

The product of its (nonzero) digits is 980, while the sum is 25.

The square root of 21071572 is about 4590.3781979266. The cubic root of 21071572 is about 276.2054935364.

Adding to 21071572 its reverse (27517012), we get a palindrome (48588584).

The spelling of 21071572 in words is "twenty-one million, seventy-one thousand, five hundred seventy-two".