21010123250 has 32 divisors (see below), whose sum is σ = 39975749424. Its totient is φ = 8266272000.

The previous prime is 21010123223. The next prime is 21010123279. The reversal of 21010123250 is 5232101012.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 3389281 + 21006733969 = 1841^2 + 144937^2 .

It is an alternating number because its digits alternate between even and odd.

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, 673607 + ... + 704106.

Almost surely, 2^21010123250 is an apocalyptic number.

21010123250 is a deficient number, since it is larger than the sum of its proper divisors (18965626174).

21010123250 is a wasteful number, since it uses less digits than its factorization.

21010123250 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1377791 (or 1377781 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 17.

Adding to 21010123250 its reverse (5232101012), we get a palindrome (26242224262).

The spelling of 21010123250 in words is "twenty-one billion, ten million, one hundred twenty-three thousand, two hundred fifty".