21257673 has 16 divisors (see below), whose sum is σ = 29019840. Its totient is φ = 13837824.

The previous prime is 21257671. The next prime is 21257689. The reversal of 21257673 is 37675212.

It is not a de Polignac number, because 21257673 - 2¹ = 21257671 is a prime.

It is a super-2 number, since 2×21257673² = 903777322749858, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21257671) 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, 24318 + ... + 25176.

It is an arithmetic number, because the mean of its divisors is an integer number (1813740).

Almost surely, 2^21257673 is an apocalyptic number.

It is an amenable number.

21257673 is a deficient number, since it is larger than the sum of its proper divisors (7762167).

21257673 is a wasteful number, since it uses less digits than its factorization.

21257673 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1048.

The product of its digits is 17640, while the sum is 33.

The square root of 21257673 is about 4610.6044072334. The cubic root of 21257673 is about 277.0162467066.

The spelling of 21257673 in words is "twenty-one million, two hundred fifty-seven thousand, six hundred seventy-three".