21585502631 has 32 divisors (see below), whose sum is σ = 27682103808. Its totient is φ = 16339847040.

The previous prime is 21585502613. The next prime is 21585502649. The reversal of 21585502631 is 13620558512.

It is an interprime number because it is at equal distance from previous prime (21585502613) and next prime (21585502649).

It is not a de Polignac number, because 21585502631 - 2⁶ = 21585502567 is a prime.

It is a super-2 number, since 2×21585502631² (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 (21585502681) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1940321 + ... + 1951413.

It is an arithmetic number, because the mean of its divisors is an integer number (865065744).

Almost surely, 2^21585502631 is an apocalyptic number.

21585502631 is a deficient number, since it is larger than the sum of its proper divisors (6096601177).

21585502631 is a wasteful number, since it uses less digits than its factorization.

21585502631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11831.

The product of its (nonzero) digits is 72000, while the sum is 38.

The spelling of 21585502631 in words is "twenty-one billion, five hundred eighty-five million, five hundred two thousand, six hundred thirty-one".