21310540 has 12 divisors (see below), whose sum is σ = 44752176. Its totient is φ = 8524208.

The previous prime is 21310519. The next prime is 21310561. The reversal of 21310540 is 4501312.

It is an interprime number because it is at equal distance from previous prime (21310519) and next prime (21310561).

It is a super-3 number, since 3×21310540³ (a number of 23 digits) contains 333 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 532744 + ... + 532783.

It is an arithmetic number, because the mean of its divisors is an integer number (3729348).

Almost surely, 2^21310540 is an apocalyptic number.

21310540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21310540 is an abundant number, since it is smaller than the sum of its proper divisors (23441636).

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

21310540 is a wasteful number, since it uses less digits than its factorization.

21310540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1065536 (or 1065534 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 16.

The square root of 21310540 is about 4616.3340433725. The cubic root of 21310540 is about 277.2456994495.

Adding to 21310540 its reverse (4501312), we get a palindrome (25811852).

The spelling of 21310540 in words is "twenty-one million, three hundred ten thousand, five hundred forty".