21011932751 has 4 divisors (see below), whose sum is σ = 21019469400. Its totient is φ = 21004396104.

The previous prime is 21011932699. The next prime is 21011932787. The reversal of 21011932751 is 15723911012.

It is a happy number.

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-21011932751 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 (21011932351) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3764141 + ... + 3769718.

It is an arithmetic number, because the mean of its divisors is an integer number (5254867350).

Almost surely, 2^21011932751 is an apocalyptic number.

21011932751 is a deficient number, since it is larger than the sum of its proper divisors (7536649).

21011932751 is an equidigital number, since it uses as much as digits as its factorization.

21011932751 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7536648.

The product of its (nonzero) digits is 3780, while the sum is 32.

The spelling of 21011932751 in words is "twenty-one billion, eleven million, nine hundred thirty-two thousand, seven hundred fifty-one".