21121774081768 has 32 divisors (see below), whose sum is σ = 39982065021000. Its totient is φ = 10460291657728.

The previous prime is 21121774081717. The next prime is 21121774081799. The reversal of 21121774081768 is 86718047712112.

It can be written as a sum of positive squares in 4 ways, for example, as 18476603627364 + 2645170454404 = 4298442^2 + 1626398^2 .

It is a super-2 number, since 2×21121774081768² (a number of 27 digits) contains 22 as substring.

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, 24677821 + ... + 25519372.

Almost surely, 2^{21121774081768} is an apocalyptic number.

It is an amenable number.

21121774081768 is a deficient number, since it is larger than the sum of its proper divisors (18860290939232).

21121774081768 is a wasteful number, since it uses less digits than its factorization.

21121774081768 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50197701 (or 50197697 counting only the distinct ones).

The product of its (nonzero) digits is 2107392, while the sum is 55.

The spelling of 21121774081768 in words is "twenty-one trillion, one hundred twenty-one billion, seven hundred seventy-four million, eighty-one thousand, seven hundred sixty-eight".