21002081493 has 8 divisors (see below), whose sum is σ = 28007523648. Its totient is φ = 13999013504.

The previous prime is 21002081467. The next prime is 21002081521. The reversal of 21002081493 is 39418020012.

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 21002081493 - 2⁸ = 21002081237 is a prime.

It is a super-2 number, since 2×21002081493² (a number of 21 digits) contains 22 as substring.

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 21002081493.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21002081393) 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, 572796 + ... + 608357.

It is an arithmetic number, because the mean of its divisors is an integer number (3500940456).

Almost surely, 2^21002081493 is an apocalyptic number.

It is an amenable number.

21002081493 is a deficient number, since it is larger than the sum of its proper divisors (7005442155).

21002081493 is a wasteful number, since it uses less digits than its factorization.

21002081493 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1187083.

The product of its (nonzero) digits is 3456, while the sum is 30.

The spelling of 21002081493 in words is "twenty-one billion, two million, eighty-one thousand, four hundred ninety-three".