21340375 has 32 divisors (see below), whose sum is σ = 31524480. Its totient is φ = 14128800.

The previous prime is 21340373. The next prime is 21340381. The reversal of 21340375 is 57304312.

It is not a de Polignac number, because 21340375 - 2¹ = 21340373 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21340373) 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, 735861 + ... + 735889.

It is an arithmetic number, because the mean of its divisors is an integer number (985140).

Almost surely, 2^21340375 is an apocalyptic number.

21340375 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21340375 is a deficient number, since it is larger than the sum of its proper divisors (10184105).

21340375 is an frugal number, since it uses more digits than its factorization.

21340375 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 109 (or 41 counting only the distinct ones).

The product of its (nonzero) digits is 2520, while the sum is 25.

The square root of 21340375 is about 4619.5643734015. The cubic root of 21340375 is about 277.3750215020.

Adding to 21340375 its reverse (57304312), we get a palindrome (78644687).

The spelling of 21340375 in words is "twenty-one million, three hundred forty thousand, three hundred seventy-five".