21342040 has 32 divisors (see below), whose sum is σ = 48930480. Its totient is φ = 8374912.

The previous prime is 21342031. The next prime is 21342047. The reversal of 21342040 is 4024312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21342047) 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, 2914 + ... + 7153.

Almost surely, 2^21342040 is an apocalyptic number.

21342040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21342040 is an abundant number, since it is smaller than the sum of its proper divisors (27588440).

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

21342040 is a wasteful number, since it uses less digits than its factorization.

21342040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10131 (or 10127 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 16.

The square root of 21342040 is about 4619.7445816841. The cubic root of 21342040 is about 277.3822350179.

Adding to 21342040 its reverse (4024312), we get a palindrome (25366352).

The spelling of 21342040 in words is "twenty-one million, three hundred forty-two thousand, forty".