21771157767 has 8 divisors (see below), whose sum is σ = 29029394160. Its totient is φ = 14513513280.

The previous prime is 21771157739. The next prime is 21771157787. The reversal of 21771157767 is 76775117712.

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 21771157767 - 2⁸ = 21771157511 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21771157787) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 53542 + ... + 215427.

It is an arithmetic number, because the mean of its divisors is an integer number (3628674270).

Almost surely, 2^21771157767 is an apocalyptic number.

21771157767 is a deficient number, since it is larger than the sum of its proper divisors (7258236393).

21771157767 is a wasteful number, since it uses less digits than its factorization.

21771157767 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 295953.

The product of its digits is 1008420, while the sum is 51.

The spelling of 21771157767 in words is "twenty-one billion, seven hundred seventy-one million, one hundred fifty-seven thousand, seven hundred sixty-seven".