21142817577 has 18 divisors (see below), whose sum is σ = 35525687418. Its totient is φ = 12081609792.

The previous prime is 21142817569. The next prime is 21142817581. The reversal of 21142817577 is 77571824112.

It is a happy number.

21142817577 is a `hidden beast` number, since 21 + 1 + 42 + 8 + 17 + 577 = 666.

It can be written as a sum of positive squares in only one way, i.e., 13948554816 + 7194262761 = 118104^2 + 84819^2 .

It is not a de Polignac number, because 21142817577 - 2³ = 21142817569 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21142817177) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 23971008 + ... + 23971889.

It is an arithmetic number, because the mean of its divisors is an integer number (1973649301).

Almost surely, 2^21142817577 is an apocalyptic number.

It is an amenable number.

21142817577 is a deficient number, since it is larger than the sum of its proper divisors (14382869841).

21142817577 is a wasteful number, since it uses less digits than its factorization.

21142817577 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47942917 (or 47942907 counting only the distinct ones).

The product of its digits is 219520, while the sum is 45.

The spelling of 21142817577 in words is "twenty-one billion, one hundred forty-two million, eight hundred seventeen thousand, five hundred seventy-seven".