21142647 has 16 divisors (see below), whose sum is σ = 31444480. Its totient is φ = 14040216.

The previous prime is 21142643. The next prime is 21142663. The reversal of 21142647 is 74624112.

21142647 is a `hidden beast` number, since 2 + 1 + 14 + 2 + 647 = 666.

It is not a de Polignac number, because 21142647 - 2² = 21142643 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21142647.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21142643) 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 15 ways as a sum of consecutive naturals, for example, 6258 + ... + 9024.

It is an arithmetic number, because the mean of its divisors is an integer number (1965280).

Almost surely, 2^21142647 is an apocalyptic number.

21142647 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

21142647 is a deficient number, since it is larger than the sum of its proper divisors (10301833).

21142647 is a wasteful number, since it uses less digits than its factorization.

21142647 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3059 (or 3053 counting only the distinct ones).

The product of its digits is 2688, while the sum is 27.

The square root of 21142647 is about 4598.1134174790. The cubic root of 21142647 is about 276.5156946359.

Adding to 21142647 its reverse (74624112), we get a palindrome (95766759).

It can be divided in two parts, 2114 and 2647, that added together give a square (4761 = 69²).

The spelling of 21142647 in words is "twenty-one million, one hundred forty-two thousand, six hundred forty-seven".