21256670166250 has 40 divisors (see below), whose sum is σ = 39879432574740. Its totient is φ = 8495000544000.

The previous prime is 21256670166241. The next prime is 21256670166271. The reversal of 21256670166250 is 5266107665212.

It can be written as a sum of positive squares in 10 ways, for example, as 2601017396289 + 18655652769961 = 1612767^2 + 4319219^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21256670166194 and 21256670166203.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 6280719 + ... + 9053218.

Almost surely, 2^{21256670166250} is an apocalyptic number.

21256670166250 is a deficient number, since it is larger than the sum of its proper divisors (18622762408490).

21256670166250 is a wasteful number, since it uses less digits than its factorization.

21256670166250 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15335068 (or 15335053 counting only the distinct ones).

The product of its (nonzero) digits is 1814400, while the sum is 49.

The spelling of 21256670166250 in words is "twenty-one trillion, two hundred fifty-six billion, six hundred seventy million, one hundred sixty-six thousand, two hundred fifty".