21787737044 has 6 divisors (see below), whose sum is σ = 38128539834. Its totient is φ = 10893868520.

The previous prime is 21787737029. The next prime is 21787737067. The reversal of 21787737044 is 44073778712.

It can be written as a sum of positive squares in only one way, i.e., 13400840644 + 8386896400 = 115762^2 + 91580^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21787736983 and 21787737001.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2723467127 + ... + 2723467134.

It is an arithmetic number, because the mean of its divisors is an integer number (6354756639).

Almost surely, 2^21787737044 is an apocalyptic number.

It is an amenable number.

21787737044 is a deficient number, since it is larger than the sum of its proper divisors (16340802790).

21787737044 is a wasteful number, since it uses less digits than its factorization.

21787737044 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5446934265 (or 5446934263 counting only the distinct ones).

The product of its (nonzero) digits is 1843968, while the sum is 50.

The spelling of 21787737044 in words is "twenty-one billion, seven hundred eighty-seven million, seven hundred thirty-seven thousand, forty-four".