21425340 has 48 divisors (see below), whose sum is σ = 61931520. Its totient is φ = 5528640.

The previous prime is 21425333. The next prime is 21425347. The reversal of 21425340 is 4352412.

It is an interprime number because it is at equal distance from previous prime (21425333) and next prime (21425347).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21425347) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3900 + ... + 7619.

It is an arithmetic number, because the mean of its divisors is an integer number (1290240).

Almost surely, 2^21425340 is an apocalyptic number.

21425340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21425340 is an abundant number, since it is smaller than the sum of its proper divisors (40506180).

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

21425340 is a wasteful number, since it uses less digits than its factorization.

21425340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11562 (or 11560 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 21.

The square root of 21425340 is about 4628.7514515256. The cubic root of 21425340 is about 277.7426495430.

Adding to 21425340 its reverse (4352412), we get a palindrome (25777752).

The spelling of 21425340 in words is "twenty-one million, four hundred twenty-five thousand, three hundred forty".