21961028 has 12 divisors (see below), whose sum is σ = 38958780. Its totient is φ = 10829952.

The previous prime is 21961013. The next prime is 21961031. The reversal of 21961028 is 82016912.

It can be written as a sum of positive squares in 2 ways, for example, as 17156164 + 4804864 = 4142^2 + 2192^2 .

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 37313 + ... + 37896.

It is an arithmetic number, because the mean of its divisors is an integer number (3246565).

Almost surely, 2^21961028 is an apocalyptic number.

It is an amenable number.

21961028 is a deficient number, since it is larger than the sum of its proper divisors (16997752).

21961028 is a wasteful number, since it uses less digits than its factorization.

21961028 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 75286 (or 75284 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 29.

The square root of 21961028 is about 4686.2594891875. The cubic root of 21961028 is about 280.0383790929.

The spelling of 21961028 in words is "twenty-one million, nine hundred sixty-one thousand, twenty-eight".