21166494 has 32 divisors (see below), whose sum is σ = 45118080. Its totient is φ = 6600672.

The previous prime is 21166489. The next prime is 21166499. The reversal of 21166494 is 49466112.

It is an interprime number because it is at equal distance from previous prime (21166489) and next prime (21166499).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21166499) 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, 8344 + ... + 10580.

It is an arithmetic number, because the mean of its divisors is an integer number (1409940).

Almost surely, 2^21166494 is an apocalyptic number.

21166494 is an abundant number, since it is smaller than the sum of its proper divisors (23951586).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21166494 is a wasteful number, since it uses less digits than its factorization.

21166494 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2344.

The product of its digits is 10368, while the sum is 33.

The square root of 21166494 is about 4600.7058154157. The cubic root of 21166494 is about 276.6196171666.

It can be divided in two parts, 2116649 and 4, that added together give a triangular number (2116653 = T₂₀₅₇).

The spelling of 21166494 in words is "twenty-one million, one hundred sixty-six thousand, four hundred ninety-four".