21774973445721 has 6 divisors (see below), whose sum is σ = 31452739421610. Its totient is φ = 14516648963808.

The previous prime is 21774973445699. The next prime is 21774973445761. The reversal of 21774973445721 is 12754437947712.

21774973445721 is a `hidden beast` number, since 2 + 1 + 7 + 7 + 497 + 34 + 45 + 72 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 16279699805721 + 5495273640000 = 4034811^2 + 2344200^2 .

It is not a de Polignac number, because 21774973445721 - 2¹⁸ = 21774973183577 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21774973445761) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1209720746976 + ... + 1209720746993.

It is an arithmetic number, because the mean of its divisors is an integer number (5242123236935).

Almost surely, 2^{21774973445721} is an apocalyptic number.

It is an amenable number.

21774973445721 is a deficient number, since it is larger than the sum of its proper divisors (9677765975889).

21774973445721 is a wasteful number, since it uses less digits than its factorization.

21774973445721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2419441493975 (or 2419441493972 counting only the distinct ones).

The product of its digits is 82978560, while the sum is 63.

The spelling of 21774973445721 in words is "twenty-one trillion, seven hundred seventy-four billion, nine hundred seventy-three million, four hundred forty-five thousand, seven hundred twenty-one".