21177702071 has 4 divisors (see below), whose sum is σ = 21432855192. Its totient is φ = 20922548952.

The previous prime is 21177702061. The next prime is 21177702083. The reversal of 21177702071 is 17020777112.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21177702071 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21177702031) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 127576436 + ... + 127576601.

It is an arithmetic number, because the mean of its divisors is an integer number (5358213798).

Almost surely, 2^21177702071 is an apocalyptic number.

21177702071 is a deficient number, since it is larger than the sum of its proper divisors (255153121).

21177702071 is an equidigital number, since it uses as much as digits as its factorization.

21177702071 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 255153120.

The product of its (nonzero) digits is 9604, while the sum is 35.

The spelling of 21177702071 in words is "twenty-one billion, one hundred seventy-seven million, seven hundred two thousand, seventy-one".