21581630239 has 8 divisors (see below), whose sum is σ = 23419175472. Its totient is φ = 19769430720.

The previous prime is 21581630221. The next prime is 21581630243. The reversal of 21581630239 is 93203618512.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21581630239 - 2¹¹ = 21581628191 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 (21581630249) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6334654 + ... + 6338059.

It is an arithmetic number, because the mean of its divisors is an integer number (2927396934).

Almost surely, 2^21581630239 is an apocalyptic number.

21581630239 is a deficient number, since it is larger than the sum of its proper divisors (1837545233).

21581630239 is a wasteful number, since it uses less digits than its factorization.

21581630239 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12672857.

The product of its (nonzero) digits is 77760, while the sum is 40.

The spelling of 21581630239 in words is "twenty-one billion, five hundred eighty-one million, six hundred thirty thousand, two hundred thirty-nine".