21351594 has 16 divisors (see below), whose sum is σ = 46585440. Its totient is φ = 6470160.

The previous prime is 21351593. The next prime is 21351601. The reversal of 21351594 is 49515312.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21351593) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 161689 + ... + 161820.

It is an arithmetic number, because the mean of its divisors is an integer number (2911590).

Almost surely, 2^21351594 is an apocalyptic number.

21351594 is an abundant number, since it is smaller than the sum of its proper divisors (25233846).

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

21351594 is a wasteful number, since it uses less digits than its factorization.

21351594 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 323525.

The product of its digits is 5400, while the sum is 30.

The square root of 21351594 is about 4620.7785058364. The cubic root of 21351594 is about 277.4236199170.

It can be divided in two parts, 21351 and 594, that added together give a triangular number (21945 = T₂₀₉).

The spelling of 21351594 in words is "twenty-one million, three hundred fifty-one thousand, five hundred ninety-four".