21402342 has 24 divisors (see below), whose sum is σ = 49939344. Its totient is φ = 6585264.

The previous prime is 21402331. The next prime is 21402373. The reversal of 21402342 is 24320412.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 45498 + ... + 45965.

It is an arithmetic number, because the mean of its divisors is an integer number (2080806).

Almost surely, 2^21402342 is an apocalyptic number.

21402342 is an abundant number, since it is smaller than the sum of its proper divisors (28537002).

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

21402342 is a wasteful number, since it uses less digits than its factorization.

21402342 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91484 (or 91481 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 18.

The square root of 21402342 is about 4626.2665292869. The cubic root of 21402342 is about 277.6432374718.

Adding to 21402342 its reverse (24320412), we get a palindrome (45722754).

The spelling of 21402342 in words is "twenty-one million, four hundred two thousand, three hundred forty-two".