90217167421 has 2 divisors, whose sum is σ = 90217167422. Its totient is φ = 90217167420.

The previous prime is 90217167401. The next prime is 90217167433. The reversal of 90217167421 is 12476171209.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 87385863321 + 2831304100 = 295611^2 + 53210^2 .

It is a cyclic number.

It is not a de Polignac number, because 90217167421 - 2¹⁹ = 90216643133 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (90217167401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45108583710 + 45108583711.

It is an arithmetic number, because the mean of its divisors is an integer number (45108583711).

Almost surely, 2^90217167421 is an apocalyptic number.

It is an amenable number.

90217167421 is a deficient number, since it is larger than the sum of its proper divisors (1).

90217167421 is an equidigital number, since it uses as much as digits as its factorization.

90217167421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 42336, while the sum is 40.

The spelling of 90217167421 in words is "ninety billion, two hundred seventeen million, one hundred sixty-seven thousand, four hundred twenty-one".