21210110209978 has 32 divisors (see below), whose sum is σ = 32034792746880. Its totient is φ = 10532124096000.

The previous prime is 21210110209927. The next prime is 21210110209993. The reversal of 21210110209978 is 87990201101212.

It is a happy 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, 282722493 + ... + 282797503.

It is an arithmetic number, because the mean of its divisors is an integer number (1001087273340).

Almost surely, 2^{21210110209978} is an apocalyptic number.

21210110209978 is a deficient number, since it is larger than the sum of its proper divisors (10824682536902).

21210110209978 is a wasteful number, since it uses less digits than its factorization.

21210110209978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76854.

The product of its (nonzero) digits is 36288, while the sum is 43.

The spelling of 21210110209978 in words is "twenty-one trillion, two hundred ten billion, one hundred ten million, two hundred nine thousand, nine hundred seventy-eight".