87990211210021 has 8 divisors (see below), whose sum is σ = 89115612540800. Its totient is φ = 86865099909120.

The previous prime is 87990211209991. The next prime is 87990211210051. The reversal of 87990211210021 is 12001211209978.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (87990211209991) and next prime (87990211210051).

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 87990211210021 - 2⁷ = 87990211209893 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 87990211210021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (87990211210051) 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, 71896791 + ... + 73110388.

It is an arithmetic number, because the mean of its divisors is an integer number (11139451567600).

Almost surely, 2^{87990211210021} is an apocalyptic number.

It is an amenable number.

87990211210021 is a deficient number, since it is larger than the sum of its proper divisors (1125401330779).

87990211210021 is a wasteful number, since it uses less digits than its factorization.

87990211210021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 145014939.

The product of its (nonzero) digits is 36288, while the sum is 43.

Subtracting from 87990211210021 its sum of digits (43), we obtain a palindrome (87990211209978).

Adding to 87990211210021 its reverse (12001211209978), we get a palindrome (99991422419999).

The spelling of 87990211210021 in words is "eighty-seven trillion, nine hundred ninety billion, two hundred eleven million, two hundred ten thousand, twenty-one".