21092390 has 16 divisors (see below), whose sum is σ = 41418000. Its totient is φ = 7669920.

The previous prime is 21092371. The next prime is 21092399. The reversal of 21092390 is 9329012.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21092399) 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, 95765 + ... + 95984.

It is an arithmetic number, because the mean of its divisors is an integer number (2588625).

Almost surely, 2^21092390 is an apocalyptic number.

21092390 is a deficient number, since it is larger than the sum of its proper divisors (20325610).

21092390 is a wasteful number, since it uses less digits than its factorization.

21092390 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 191767.

The product of its (nonzero) digits is 972, while the sum is 26.

The square root of 21092390 is about 4592.6452072852. The cubic root of 21092390 is about 276.2964241574.

The spelling of 21092390 in words is "twenty-one million, ninety-two thousand, three hundred ninety".