91020121 has 4 divisors (see below), whose sum is σ = 93136912. Its totient is φ = 88903332.

The previous prime is 91020101. The next prime is 91020143. The reversal of 91020121 is 12102019.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12102019 = 29 ⋅417311.

It is a cyclic number.

It is not a de Polignac number, because 91020121 - 2¹⁷ = 90889049 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 91020095 and 91020104.

It is not an unprimeable number, because it can be changed into a prime (91020101) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1058331 + ... + 1058416.

It is an arithmetic number, because the mean of its divisors is an integer number (23284228).

Almost surely, 2^91020121 is an apocalyptic number.

It is an amenable number.

91020121 is a deficient number, since it is larger than the sum of its proper divisors (2116791).

91020121 is a wasteful number, since it uses less digits than its factorization.

91020121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2116790.

The product of its (nonzero) digits is 36, while the sum is 16.

The square root of 91020121 is about 9540.4465828388. The cubic root of 91020121 is about 449.8272933958.

The spelling of 91020121 in words is "ninety-one million, twenty thousand, one hundred twenty-one".