2102011687921 has 2 divisors, whose sum is σ = 2102011687922. Its totient is φ = 2102011687920.

The previous prime is 2102011687913. The next prime is 2102011687999. The reversal of 2102011687921 is 1297861102012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1492502022400 + 609509665521 = 1221680^2 + 780711^2 .

It is a cyclic number.

It is not a de Polignac number, because 2102011687921 - 2³ = 2102011687913 is a prime.

It is not a weakly prime, because it can be changed into another prime (2102011687901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1051005843960 + 1051005843961.

It is an arithmetic number, because the mean of its divisors is an integer number (1051005843961).

Almost surely, 2^{2102011687921} is an apocalyptic number.

It is an amenable number.

2102011687921 is a deficient number, since it is larger than the sum of its proper divisors (1).

2102011687921 is an equidigital number, since it uses as much as digits as its factorization.

2102011687921 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 24192, while the sum is 40.

Adding to 2102011687921 its reverse (1297861102012), we get a palindrome (3399872789933).

The spelling of 2102011687921 in words is "two trillion, one hundred two billion, eleven million, six hundred eighty-seven thousand, nine hundred twenty-one".