21473866 has 4 divisors (see below), whose sum is σ = 32210802. Its totient is φ = 10736932.

The previous prime is 21473827. The next prime is 21473867. The reversal of 21473866 is 66837412.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 21427641 + 46225 = 4629^2 + 215^2 .

It is a super-2 number, since 2×21473866² = 922253841971912, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21473867) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5368465 + ... + 5368468.

Almost surely, 2^21473866 is an apocalyptic number.

21473866 is a deficient number, since it is larger than the sum of its proper divisors (10736936).

21473866 is a wasteful number, since it uses less digits than its factorization.

21473866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10736935.

The product of its digits is 48384, while the sum is 37.

The square root of 21473866 is about 4633.9902891569. The cubic root of 21473866 is about 277.9521767882.

The spelling of 21473866 in words is "twenty-one million, four hundred seventy-three thousand, eight hundred sixty-six".