21025690 has 16 divisors (see below), whose sum is σ = 43252992. Its totient is φ = 7208784.

The previous prime is 21025681. The next prime is 21025691. The reversal of 21025690 is 9652012.

It is a super-2 number, since 2×21025690² = 884159279952200, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21025691) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 150114 + ... + 150253.

It is an arithmetic number, because the mean of its divisors is an integer number (2703312).

Almost surely, 2^21025690 is an apocalyptic number.

21025690 is an abundant number, since it is smaller than the sum of its proper divisors (22227302).

21025690 is a wasteful number, since it uses less digits than its factorization.

21025690 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 300381.

The product of its (nonzero) digits is 1080, while the sum is 25.

The square root of 21025690 is about 4585.3778470263. The cubic root of 21025690 is about 276.0048745901.

The spelling of 21025690 in words is "twenty-one million, twenty-five thousand, six hundred ninety".