19910901901 has 16 divisors (see below), whose sum is σ = 22705233408. Its totient is φ = 17283380400.

The previous prime is 19910901883. The next prime is 19910901919. The reversal of 19910901901 is 10910901991.

It is an interprime number because it is at equal distance from previous prime (19910901883) and next prime (19910901919).

It is not a de Polignac number, because 19910901901 - 2¹⁷ = 19910770829 is a prime.

It is a super-2 number, since 2×19910901901² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19910901601) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 75550 + ... + 213376.

It is an arithmetic number, because the mean of its divisors is an integer number (1419077088).

Almost surely, 2^19910901901 is an apocalyptic number.

19910901901 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

19910901901 is a deficient number, since it is larger than the sum of its proper divisors (2794331507).

19910901901 is a wasteful number, since it uses less digits than its factorization.

19910901901 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 138432.

The product of its (nonzero) digits is 6561, while the sum is 40.

It can be divided in two parts, 1991090 and 1901, that added together give a palindrome (1992991).

The spelling of 19910901901 in words is "nineteen billion, nine hundred ten million, nine hundred one thousand, nine hundred one".