21047667 has 16 divisors (see below), whose sum is σ = 29125632. Its totient is φ = 13505760.

The previous prime is 21047657. The next prime is 21047669. The reversal of 21047667 is 76674012.

It is not a de Polignac number, because 21047667 - 2⁶ = 21047603 is a prime.

It is a super-2 number, since 2×21047667² = 886008572285778, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21047669) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 20613 + ... + 21609.

It is an arithmetic number, because the mean of its divisors is an integer number (1820352).

Almost surely, 2^21047667 is an apocalyptic number.

21047667 is a deficient number, since it is larger than the sum of its proper divisors (8077965).

21047667 is a wasteful number, since it uses less digits than its factorization.

21047667 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1258.

The product of its (nonzero) digits is 14112, while the sum is 33.

The square root of 21047667 is about 4587.7736430648. The cubic root of 21047667 is about 276.1010053545.

The spelling of 21047667 in words is "twenty-one million, forty-seven thousand, six hundred sixty-seven".