21639555577 has 8 divisors (see below), whose sum is σ = 21751906176. Its totient is φ = 21527433312.

The previous prime is 21639555569. The next prime is 21639555643. The reversal of 21639555577 is 77555593612.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21639555577 - 2³ = 21639555569 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21639555277) 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, 134613 + ... + 247789.

It is an arithmetic number, because the mean of its divisors is an integer number (2718988272).

Almost surely, 2^21639555577 is an apocalyptic number.

It is an amenable number.

21639555577 is a deficient number, since it is larger than the sum of its proper divisors (112350599).

21639555577 is a wasteful number, since it uses less digits than its factorization.

21639555577 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 114167.

The product of its digits is 9922500, while the sum is 55.

The spelling of 21639555577 in words is "twenty-one billion, six hundred thirty-nine million, five hundred fifty-five thousand, five hundred seventy-seven".