45138991 has 8 divisors (see below), whose sum is σ = 46456704. Its totient is φ = 43831680.

The previous prime is 45138979. The next prime is 45139013. The reversal of 45138991 is 19983154.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 45138991 - 2⁵ = 45138959 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 (45138901) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6675 + ... + 11611.

It is an arithmetic number, because the mean of its divisors is an integer number (5807088).

Almost surely, 2^45138991 is an apocalyptic number.

45138991 is a gapful number since it is divisible by the number (41) formed by its first and last digit.

45138991 is a deficient number, since it is larger than the sum of its proper divisors (1317713).

45138991 is a wasteful number, since it uses less digits than its factorization.

45138991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5201.

The product of its digits is 38880, while the sum is 40.

The square root of 45138991 is about 6718.5557227726. Note that the first 3 decimals coincide. The cubic root of 45138991 is about 356.0551586249.

The spelling of 45138991 in words is "forty-five million, one hundred thirty-eight thousand, nine hundred ninety-one".