21087701783 has 4 divisors (see below), whose sum is σ = 21092655048. Its totient is φ = 21082748520.

The previous prime is 21087701753. The next prime is 21087701797. The reversal of 21087701783 is 38710778012.

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-21087701783 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 (21087701743) 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, 2470241 + ... + 2478762.

It is an arithmetic number, because the mean of its divisors is an integer number (5273163762).

Almost surely, 2^21087701783 is an apocalyptic number.

21087701783 is a deficient number, since it is larger than the sum of its proper divisors (4953265).

21087701783 is an equidigital number, since it uses as much as digits as its factorization.

21087701783 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4953264.

The product of its (nonzero) digits is 131712, while the sum is 44.

The spelling of 21087701783 in words is "twenty-one billion, eighty-seven million, seven hundred one thousand, seven hundred eighty-three".