1990101081 has 16 divisors (see below), whose sum is σ = 2706333120. Its totient is φ = 1300353600.

The previous prime is 1990101037. The next prime is 1990101089. The reversal of 1990101081 is 1801010991.

It is a happy number.

It is not a de Polignac number, because 1990101081 - 2²² = 1985906777 is a prime.

It is a super-2 number, since 2×1990101081² = 7921004625194737122, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1990101089) 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, 161155 + ... + 173063.

It is an arithmetic number, because the mean of its divisors is an integer number (169145820).

Almost surely, 2^1990101081 is an apocalyptic number.

It is an amenable number.

1990101081 is a deficient number, since it is larger than the sum of its proper divisors (716232039).

1990101081 is a wasteful number, since it uses less digits than its factorization.

1990101081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13016.

The product of its (nonzero) digits is 648, while the sum is 30.

The square root of 1990101081 is about 44610.5489878795. The cubic root of 1990101081 is about 1257.8389683113.

The spelling of 1990101081 in words is "one billion, nine hundred ninety million, one hundred one thousand, eighty-one".