91242421 has 2 divisors, whose sum is σ = 91242422. Its totient is φ = 91242420.

The previous prime is 91242391. The next prime is 91242443. The reversal of 91242421 is 12424219.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 59444100 + 31798321 = 7710^2 + 5639^2 .

It is a cyclic number.

It is not a de Polignac number, because 91242421 - 2⁷ = 91242293 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91242461) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45621210 + 45621211.

It is an arithmetic number, because the mean of its divisors is an integer number (45621211).

Almost surely, 2^91242421 is an apocalyptic number.

It is an amenable number.

91242421 is a deficient number, since it is larger than the sum of its proper divisors (1).

91242421 is an equidigital number, since it uses as much as digits as its factorization.

91242421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1152, while the sum is 25.

The square root of 91242421 is about 9552.0898760428. The cubic root of 91242421 is about 450.1932026354.

The spelling of 91242421 in words is "ninety-one million, two hundred forty-two thousand, four hundred twenty-one".