21577655949 has 8 divisors (see below), whose sum is σ = 28775263200. Its totient is φ = 14382576336.

The previous prime is 21577655923. The next prime is 21577655963. The reversal of 21577655949 is 94955677512.

It is a happy number.

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

It is not a de Polignac number, because 21577655949 - 2⁷ = 21577655821 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21577655892 and 21577655901.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21577655969) 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, 611899 + ... + 646200.

It is an arithmetic number, because the mean of its divisors is an integer number (3596907900).

Almost surely, 2^21577655949 is an apocalyptic number.

It is an amenable number.

21577655949 is a deficient number, since it is larger than the sum of its proper divisors (7197607251).

21577655949 is a wasteful number, since it uses less digits than its factorization.

21577655949 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1263819.

The product of its digits is 23814000, while the sum is 60.

The spelling of 21577655949 in words is "twenty-one billion, five hundred seventy-seven million, six hundred fifty-five thousand, nine hundred forty-nine".