21673161 has 12 divisors (see below), whose sum is σ = 32034288. Its totient is φ = 14112504.

The previous prime is 21673159. The next prime is 21673163. The reversal of 21673161 is 16137612.

It is an interprime number because it is at equal distance from previous prime (21673159) and next prime (21673163).

It is not a de Polignac number, because 21673161 - 2¹ = 21673159 is a prime.

It is a Smith number, since the sum of its digits (27) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (21673163) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 27615 + ... + 28388.

It is an arithmetic number, because the mean of its divisors is an integer number (2669524).

Almost surely, 2^21673161 is an apocalyptic number.

It is an amenable number.

21673161 is a deficient number, since it is larger than the sum of its proper divisors (10361127).

21673161 is a wasteful number, since it uses less digits than its factorization.

21673161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56052 (or 56049 counting only the distinct ones).

The product of its digits is 1512, while the sum is 27.

The square root of 21673161 is about 4655.4442322941. Note that the first 3 decimals coincide. The cubic root of 21673161 is about 278.8094046478.

The spelling of 21673161 in words is "twenty-one million, six hundred seventy-three thousand, one hundred sixty-one".