21961304587 has 8 divisors (see below), whose sum is σ = 21986854704. Its totient is φ = 21935772768.

The previous prime is 21961304543. The next prime is 21961304591. The reversal of 21961304587 is 78540316912.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21961304587 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21961304507) 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, 4637673 + ... + 4642405.

It is an arithmetic number, because the mean of its divisors is an integer number (2748356838).

It is a 1-persistent number, because it is pandigital, but 2⋅21961304587 = 43922609174 is not.

Almost surely, 2^21961304587 is an apocalyptic number.

21961304587 is a deficient number, since it is larger than the sum of its proper divisors (25550117).

21961304587 is a wasteful number, since it uses less digits than its factorization.

21961304587 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9149.

The product of its (nonzero) digits is 362880, while the sum is 46.

The spelling of 21961304587 in words is "twenty-one billion, nine hundred sixty-one million, three hundred four thousand, five hundred eighty-seven".