21486669 has 16 divisors (see below), whose sum is σ = 30125952. Its totient is φ = 13595648.

The previous prime is 21486649. The next prime is 21486671. The reversal of 21486669 is 96668412.

It is a cyclic number.

It is not a de Polignac number, because 21486669 - 2⁵ = 21486637 is a prime.

It is a super-2 number, since 2×21486669² = 923353889431122, which contains 22 as substring.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21486669.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21486649) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8317 + ... + 10589.

It is an arithmetic number, because the mean of its divisors is an integer number (1882872).

Almost surely, 2^21486669 is an apocalyptic number.

It is an amenable number.

21486669 is a deficient number, since it is larger than the sum of its proper divisors (8639283).

21486669 is a wasteful number, since it uses less digits than its factorization.

21486669 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2436.

The product of its digits is 124416, while the sum is 42.

The square root of 21486669 is about 4635.3715061471. The cubic root of 21486669 is about 278.0074053891.

It can be divided in two parts, 21486 and 669, that added together give a triangular number (22155 = T₂₁₀).

The spelling of 21486669 in words is "twenty-one million, four hundred eighty-six thousand, six hundred sixty-nine".