21002192641 has 8 divisors (see below), whose sum is σ = 21583190664. Its totient is φ = 20424468480.

The previous prime is 21002192633. The next prime is 21002192647. The reversal of 21002192641 is 14629120012.

It can be written as a sum of positive squares in 4 ways, for example, as 6053462416 + 14948730225 = 77804^2 + 122265^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 21002192641 - 2³ = 21002192633 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21002192647) 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, 805456 + ... + 831121.

It is an arithmetic number, because the mean of its divisors is an integer number (2697898833).

Almost surely, 2^21002192641 is an apocalyptic number.

It is an amenable number.

21002192641 is a deficient number, since it is larger than the sum of its proper divisors (580998023).

21002192641 is a wasteful number, since it uses less digits than its factorization.

21002192641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1636931.

The product of its (nonzero) digits is 1728, while the sum is 28.

The spelling of 21002192641 in words is "twenty-one billion, two million, one hundred ninety-two thousand, six hundred forty-one".