21156005606 has 32 divisors (see below), whose sum is σ = 33888365280. Its totient is φ = 9870681600.

The previous prime is 21156005599. The next prime is 21156005627. The reversal of 21156005606 is 60650065112.

It is a super-2 number, since 2×21156005606² (a number of 21 digits) contains 22 as substring.

It is a congruent 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, 9035996 + ... + 9038336.

It is an arithmetic number, because the mean of its divisors is an integer number (1059011415).

Almost surely, 2^21156005606 is an apocalyptic number.

21156005606 is a deficient number, since it is larger than the sum of its proper divisors (12732359674).

21156005606 is a wasteful number, since it uses less digits than its factorization.

21156005606 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4520.

The product of its (nonzero) digits is 10800, while the sum is 32.

The spelling of 21156005606 in words is "twenty-one billion, one hundred fifty-six million, five thousand, six hundred six".