21120506 has 16 divisors (see below), whose sum is σ = 35036928. Its totient is φ = 9468000.

The previous prime is 21120503. The next prime is 21120523. The reversal of 21120506 is 60502112.

It is not an unprimeable number, because it can be changed into a prime (21120503) 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, 4970 + ... + 8181.

It is an arithmetic number, because the mean of its divisors is an integer number (2189808).

Almost surely, 2^21120506 is an apocalyptic number.

21120506 is a deficient number, since it is larger than the sum of its proper divisors (13916422).

21120506 is a wasteful number, since it uses less digits than its factorization.

21120506 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13237.

The product of its (nonzero) digits is 120, while the sum is 17.

The square root of 21120506 is about 4595.7051689594. The cubic root of 21120506 is about 276.4191366791.

Adding to 21120506 its reverse (60502112), we get a palindrome (81622618).

The spelling of 21120506 in words is "twenty-one million, one hundred twenty thousand, five hundred six".