21512006 has 16 divisors (see below), whose sum is σ = 32931360. Its totient is φ = 10536960.

The previous prime is 21511999. The next prime is 21512017. The reversal of 21512006 is 60021512.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27590 + ... + 28358.

It is an arithmetic number, because the mean of its divisors is an integer number (2058210).

Almost surely, 2^21512006 is an apocalyptic number.

21512006 is a deficient number, since it is larger than the sum of its proper divisors (11419354).

21512006 is a wasteful number, since it uses less digits than its factorization.

21512006 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1039.

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

The square root of 21512006 is about 4638.1037073356. The cubic root of 21512006 is about 278.1166375637.

Adding to 21512006 its reverse (60021512), we get a palindrome (81533518).

It can be divided in two parts, 215 and 12006, that added together give a palindrome (12221).

The spelling of 21512006 in words is "twenty-one million, five hundred twelve thousand, six".