21040530 has 32 divisors (see below), whose sum is σ = 57711744. Its totient is φ = 4809216.

The previous prime is 21040519. The next prime is 21040541. The reversal of 21040530 is 3504012.

It is an interprime number because it is at equal distance from previous prime (21040519) and next prime (21040541).

It is a Harshad number since it is a multiple of its sum of digits (15).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 49887 + ... + 50306.

It is an arithmetic number, because the mean of its divisors is an integer number (1803492).

Almost surely, 2^21040530 is an apocalyptic number.

21040530 is an abundant number, since it is smaller than the sum of its proper divisors (36671214).

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

21040530 is a wasteful number, since it uses less digits than its factorization.

21040530 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 100210.

The product of its (nonzero) digits is 120, while the sum is 15.

The square root of 21040530 is about 4586.9957488535. The cubic root of 21040530 is about 276.0697943633.

Adding to 21040530 its reverse (3504012), we get a palindrome (24544542).

The spelling of 21040530 in words is "twenty-one million, forty thousand, five hundred thirty".