900101991 has 16 divisors (see below), whose sum is σ = 1264125440. Its totient is φ = 568114560.

The previous prime is 900101977. The next prime is 900101999. The reversal of 900101991 is 199101009.

It is not a de Polignac number, because 900101991 - 2¹⁷ = 899970919 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 (900101999) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 102546 + ... + 110976.

It is an arithmetic number, because the mean of its divisors is an integer number (79007840).

Almost surely, 2^900101991 is an apocalyptic number.

900101991 is a deficient number, since it is larger than the sum of its proper divisors (364023449).

900101991 is a wasteful number, since it uses less digits than its factorization.

900101991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10326.

The product of its (nonzero) digits is 729, while the sum is 30.

The square root of 900101991 is about 30001.6998018446. The cubic root of 900101991 is about 965.5258540532.

The spelling of 900101991 in words is "nine hundred million, one hundred one thousand, nine hundred ninety-one".