21010620506 has 16 divisors (see below), whose sum is σ = 32147327304. Its totient is φ = 10295298624.

The previous prime is 21010620469. The next prime is 21010620557. The reversal of 21010620506 is 60502601012.

It can be written as a sum of positive squares in 4 ways, for example, as 18745717225 + 2264903281 = 136915^2 + 47591^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20045 + ... + 205968.

Almost surely, 2^21010620506 is an apocalyptic number.

21010620506 is a deficient number, since it is larger than the sum of its proper divisors (11136706798).

21010620506 is a wasteful number, since it uses less digits than its factorization.

21010620506 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 226945.

The product of its (nonzero) digits is 720, while the sum is 23.

The spelling of 21010620506 in words is "twenty-one billion, ten million, six hundred twenty thousand, five hundred six".