21042015031 has 4 divisors (see below), whose sum is σ = 21147754000. Its totient is φ = 20936276064.

The previous prime is 21042014923. The next prime is 21042015061. The reversal of 21042015031 is 13051024012.

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

It is a cyclic number.

It is not a de Polignac number, because 21042015031 - 2²¹ = 21039917879 is a prime.

It is a super-2 number, since 2×21042015031² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21042015061) 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, 52869186 + ... + 52869583.

It is an arithmetic number, because the mean of its divisors is an integer number (5286938500).

Almost surely, 2^21042015031 is an apocalyptic number.

21042015031 is a deficient number, since it is larger than the sum of its proper divisors (105738969).

21042015031 is a wasteful number, since it uses less digits than its factorization.

21042015031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 105738968.

The product of its (nonzero) digits is 240, while the sum is 19.

Adding to 21042015031 its reverse (13051024012), we get a palindrome (34093039043).

The spelling of 21042015031 in words is "twenty-one billion, forty-two million, fifteen thousand, thirty-one".