21661031266156 has 6 divisors (see below), whose sum is σ = 37906804715780. Its totient is φ = 10830515633076.

The previous prime is 21661031266103. The next prime is 21661031266177. The reversal of 21661031266156 is 65166213016612.

It is a happy number.

It is a super-2 number, since 2×21661031266156² (a number of 27 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2707628908266 + ... + 2707628908273.

Almost surely, 2^{21661031266156} is an apocalyptic number.

It is an amenable number.

21661031266156 is a deficient number, since it is larger than the sum of its proper divisors (16245773449624).

21661031266156 is a wasteful number, since it uses less digits than its factorization.

21661031266156 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5415257816543 (or 5415257816541 counting only the distinct ones).

The product of its (nonzero) digits is 466560, while the sum is 46.

The spelling of 21661031266156 in words is "twenty-one trillion, six hundred sixty-one billion, thirty-one million, two hundred sixty-six thousand, one hundred fifty-six".