21070540 has 24 divisors (see below), whose sum is σ = 44547552. Its totient is φ = 8371200.

The previous prime is 21070513. The next prime is 21070541. The reversal of 21070540 is 4507012.

It is not an unprimeable number, because it can be changed into a prime (21070541) 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, 469 + ... + 6508.

It is an arithmetic number, because the mean of its divisors is an integer number (1856148).

Almost surely, 2^21070540 is an apocalyptic number.

21070540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21070540 is an abundant number, since it is smaller than the sum of its proper divisors (23477012).

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

21070540 is a wasteful number, since it uses less digits than its factorization.

21070540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7137 (or 7135 counting only the distinct ones).

The product of its (nonzero) digits is 280, while the sum is 19.

The square root of 21070540 is about 4590.2657875117. The cubic root of 21070540 is about 276.2009843217.

Adding to 21070540 its reverse (4507012), we get a palindrome (25577552).

The spelling of 21070540 in words is "twenty-one million, seventy thousand, five hundred forty".