21516662001 has 16 divisors (see below), whose sum is σ = 29622814208. Its totient is φ = 13877740800.

The previous prime is 21516661997. The next prime is 21516662009. The reversal of 21516662001 is 10026661512.

It is not a de Polignac number, because 21516662001 - 2² = 21516661997 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21516662001.

It is not an unprimeable number, because it can be changed into a prime (21516662009) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 312531 + ... + 375111.

It is an arithmetic number, because the mean of its divisors is an integer number (1851425888).

Almost surely, 2^21516662001 is an apocalyptic number.

It is an amenable number.

21516662001 is a deficient number, since it is larger than the sum of its proper divisors (8106152207).

21516662001 is a wasteful number, since it uses less digits than its factorization.

21516662001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66312.

The product of its (nonzero) digits is 4320, while the sum is 30.

The spelling of 21516662001 in words is "twenty-one billion, five hundred sixteen million, six hundred sixty-two thousand, one".