21466317977 has 8 divisors (see below), whose sum is σ = 23254365960. Its totient is φ = 19815060720.

The previous prime is 21466317937. The next prime is 21466317989. The reversal of 21466317977 is 77971366412.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 6277234441 + 15189083536 = 79229^2 + 123244^2 .

It is not a de Polignac number, because 21466317977 - 2²⁰ = 21465269401 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21466317937) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4883174 + ... + 4887567.

It is an arithmetic number, because the mean of its divisors is an integer number (2906795745).

Almost surely, 2^21466317977 is an apocalyptic number.

It is an amenable number.

21466317977 is a deficient number, since it is larger than the sum of its proper divisors (1788047983).

21466317977 is an frugal number, since it uses more digits than its factorization.

21466317977 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9770780 (or 9770754 counting only the distinct ones).

The product of its digits is 2667168, while the sum is 53.

The spelling of 21466317977 in words is "twenty-one billion, four hundred sixty-six million, three hundred seventeen thousand, nine hundred seventy-seven".