21787347601 has 4 divisors (see below), whose sum is σ = 21791329600. Its totient is φ = 21783365604.

The previous prime is 21787347599. The next prime is 21787347619. The reversal of 21787347601 is 10674378712.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21787347601 - 2¹ = 21787347599 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21787342601) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1982781 + ... + 1993738.

It is an arithmetic number, because the mean of its divisors is an integer number (5447832400).

Almost surely, 2^21787347601 is an apocalyptic number.

It is an amenable number.

21787347601 is a deficient number, since it is larger than the sum of its proper divisors (3981999).

21787347601 is an equidigital number, since it uses as much as digits as its factorization.

21787347601 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3981998.

The product of its (nonzero) digits is 395136, while the sum is 46.

The spelling of 21787347601 in words is "twenty-one billion, seven hundred eighty-seven million, three hundred forty-seven thousand, six hundred one".