21053670 has 32 divisors (see below), whose sum is σ = 55123200. Its totient is φ = 5103840.

The previous prime is 21053663. The next prime is 21053699. The reversal of 21053670 is 7635012.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21053670.

It is a congruent number.

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, 31570 + ... + 32229.

It is an arithmetic number, because the mean of its divisors is an integer number (1722600).

Almost surely, 2^21053670 is an apocalyptic number.

21053670 is an abundant number, since it is smaller than the sum of its proper divisors (34069530).

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

21053670 is a wasteful number, since it uses less digits than its factorization.

21053670 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63820.

The product of its (nonzero) digits is 1260, while the sum is 24.

The square root of 21053670 is about 4588.4278353266. The cubic root of 21053670 is about 276.1272517596.

Adding to 21053670 its reverse (7635012), we get a palindrome (28688682).

It can be divided in two parts, 2105 and 3670, that added together give a palindrome (5775).

The spelling of 21053670 in words is "twenty-one million, fifty-three thousand, six hundred seventy".