21580072 has 32 divisors (see below), whose sum is σ = 44712000. Its totient is φ = 9712384.

The previous prime is 21580057. The next prime is 21580079. The reversal of 21580072 is 27008512.

It is not an unprimeable number, because it can be changed into a prime (21580079) 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, 322 + ... + 6577.

It is an arithmetic number, because the mean of its divisors is an integer number (1397250).

Almost surely, 2^21580072 is an apocalyptic number.

It is an amenable number.

21580072 is an abundant number, since it is smaller than the sum of its proper divisors (23131928).

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

21580072 is a wasteful number, since it uses less digits than its factorization.

21580072 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6945 (or 6941 counting only the distinct ones).

The product of its (nonzero) digits is 1120, while the sum is 25.

The square root of 21580072 is about 4645.4356092836. The cubic root of 21580072 is about 278.4096577550.

Adding to 21580072 its reverse (27008512), we get a palindrome (48588584).

The spelling of 21580072 in words is "twenty-one million, five hundred eighty thousand, seventy-two".