45121991 has 6 divisors (see below), whose sum is σ = 45771576. Its totient is φ = 44481500.

The previous prime is 45121969. The next prime is 45121997. The reversal of 45121991 is 19912154.

It is not a de Polignac number, because 45121991 - 2¹⁸ = 44859847 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (45121997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 566 + ... + 9516.

It is an arithmetic number, because the mean of its divisors is an integer number (7628596).

Almost surely, 2^45121991 is an apocalyptic number.

45121991 is a deficient number, since it is larger than the sum of its proper divisors (649585).

45121991 is an frugal number, since it uses more digits than its factorization.

45121991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9093 (or 9022 counting only the distinct ones).

The product of its digits is 3240, while the sum is 32.

The square root of 45121991 is about 6717.2904507696. The cubic root of 45121991 is about 356.0104544967.

The spelling of 45121991 in words is "forty-five million, one hundred twenty-one thousand, nine hundred ninety-one".