21023394 has 64 divisors (see below), whose sum is σ = 50552832. Its totient is φ = 5702400.

The previous prime is 21023393. The next prime is 21023413. The reversal of 21023394 is 49332012.

It is not an unprimeable number, because it can be changed into a prime (21023393) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 87114 + ... + 87354.

It is an arithmetic number, because the mean of its divisors is an integer number (789888).

Almost surely, 2^21023394 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21023394, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25276416).

21023394 is an abundant number, since it is smaller than the sum of its proper divisors (29529438).

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

21023394 is a wasteful number, since it uses less digits than its factorization.

21023394 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 351.

The product of its (nonzero) digits is 1296, while the sum is 24.

The square root of 21023394 is about 4585.1274791438. The cubic root of 21023394 is about 275.9948276703.

The spelling of 21023394 in words is "twenty-one million, twenty-three thousand, three hundred ninety-four".