21053870 has 16 divisors (see below), whose sum is σ = 37987488. Its totient is φ = 8401440.

The previous prime is 21053861. The next prime is 21053873. The reversal of 21053870 is 7835012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21053873) 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, 2327 + ... + 6893.

It is an arithmetic number, because the mean of its divisors is an integer number (2374218).

Almost surely, 2^21053870 is an apocalyptic number.

21053870 is a deficient number, since it is larger than the sum of its proper divisors (16933618).

21053870 is a wasteful number, since it uses less digits than its factorization.

21053870 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5035.

The product of its (nonzero) digits is 1680, while the sum is 26.

The square root of 21053870 is about 4588.4496292321. The cubic root of 21053870 is about 276.1281261167.

Adding to 21053870 its reverse (7835012), we get a palindrome (28888882).

The spelling of 21053870 in words is "twenty-one million, fifty-three thousand, eight hundred seventy".