21612147 has 8 divisors (see below), whose sum is σ = 28903056. Its totient is φ = 14364672.

The previous prime is 21612133. The next prime is 21612179. The reversal of 21612147 is 74121612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21612147 - 2⁴ = 21612131 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is not an unprimeable number, because it can be changed into a prime (21612127) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9678 + ... + 11699.

It is an arithmetic number, because the mean of its divisors is an integer number (3612882).

Almost surely, 2^21612147 is an apocalyptic number.

21612147 is a deficient number, since it is larger than the sum of its proper divisors (7290909).

21612147 is a wasteful number, since it uses less digits than its factorization.

21612147 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21717.

The product of its digits is 672, while the sum is 24.

The square root of 21612147 is about 4648.8866409066. The cubic root of 21612147 is about 278.5475252149.

Adding to 21612147 its reverse (74121612), we get a palindrome (95733759).

The spelling of 21612147 in words is "twenty-one million, six hundred twelve thousand, one hundred forty-seven".