100891421 has 2 divisors, whose sum is σ = 100891422. Its totient is φ = 100891420.

The previous prime is 100891393. The next prime is 100891423. The reversal of 100891421 is 124198001.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 100600900 + 290521 = 10030^2 + 539^2 .

It is a cyclic number.

It is not a de Polignac number, because 100891421 - 2¹⁴ = 100875037 is a prime.

Together with 100891423, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (100891423) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 50445710 + 50445711.

It is an arithmetic number, because the mean of its divisors is an integer number (50445711).

Almost surely, 2^100891421 is an apocalyptic number.

It is an amenable number.

100891421 is a deficient number, since it is larger than the sum of its proper divisors (1).

100891421 is an equidigital number, since it uses as much as digits as its factorization.

100891421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 576, while the sum is 26.

The square root of 100891421 is about 10044.4721613433. The cubic root of 100891421 is about 465.5340086210.

It can be divided in two parts, 1008 and 91421, that added together give a palindrome (92429).

The spelling of 100891421 in words is "one hundred million, eight hundred ninety-one thousand, four hundred twenty-one".