21787680485 has 8 divisors (see below), whose sum is σ = 26146200600. Its totient is φ = 17429488384.

The previous prime is 21787680461. The next prime is 21787680503. The reversal of 21787680485 is 58408678712.

It can be written as a sum of positive squares in 4 ways, for example, as 1804465441 + 19983215044 = 42479^2 + 141362^2 .

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 21787680485 - 2¹⁰ = 21787679461 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21787680485.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 101441 + ... + 232089.

It is an arithmetic number, because the mean of its divisors is an integer number (3268275075).

Almost surely, 2^21787680485 is an apocalyptic number.

It is an amenable number.

21787680485 is a deficient number, since it is larger than the sum of its proper divisors (4358520115).

21787680485 is a wasteful number, since it uses less digits than its factorization.

21787680485 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 164007.

The product of its (nonzero) digits is 6021120, while the sum is 56.

The spelling of 21787680485 in words is "twenty-one billion, seven hundred eighty-seven million, six hundred eighty thousand, four hundred eighty-five".