21251743031 has 4 divisors (see below), whose sum is σ = 21252034752. Its totient is φ = 21251451312.

The previous prime is 21251743013. The next prime is 21251743039. The reversal of 21251743031 is 13034715212.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21251743031 is a prime.

It is a super-2 number, since 2×21251743031² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21251742985 and 21251743003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21251743039) 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, 65675 + ... + 216371.

It is an arithmetic number, because the mean of its divisors is an integer number (5313008688).

Almost surely, 2^21251743031 is an apocalyptic number.

21251743031 is a deficient number, since it is larger than the sum of its proper divisors (291721).

21251743031 is a wasteful number, since it uses less digits than its factorization.

21251743031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 291720.

The product of its (nonzero) digits is 5040, while the sum is 29.

The spelling of 21251743031 in words is "twenty-one billion, two hundred fifty-one million, seven hundred forty-three thousand, thirty-one".