21256990970 has 8 divisors (see below), whose sum is σ = 38262583764. Its totient is φ = 8502796384.

The previous prime is 21256990949. The next prime is 21256990987. The reversal of 21256990970 is 7909965212.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 18358353049 + 2898637921 = 135493^2 + 53839^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1062849539 + ... + 1062849558.

Almost surely, 2^21256990970 is an apocalyptic number.

21256990970 is a deficient number, since it is larger than the sum of its proper divisors (17005592794).

21256990970 is a wasteful number, since it uses less digits than its factorization.

21256990970 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2125699104.

The product of its (nonzero) digits is 612360, while the sum is 50.

The spelling of 21256990970 in words is "twenty-one billion, two hundred fifty-six million, nine hundred ninety thousand, nine hundred seventy".