2101949661 has 32 divisors (see below), whose sum is σ = 3257210880. Its totient is φ = 1180846656.

The previous prime is 2101949659. The next prime is 2101949677. The reversal of 2101949661 is 1669491012.

It is not a de Polignac number, because 2101949661 - 2¹ = 2101949659 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2101949611) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 909175 + ... + 911483.

It is an arithmetic number, because the mean of its divisors is an integer number (101787840).

Almost surely, 2^2101949661 is an apocalyptic number.

2101949661 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

2101949661 is a deficient number, since it is larger than the sum of its proper divisors (1155261219).

2101949661 is a wasteful number, since it uses less digits than its factorization.

2101949661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3033.

The product of its (nonzero) digits is 23328, while the sum is 39.

The square root of 2101949661 is about 45847.0245599428. The cubic root of 2101949661 is about 1280.9753432417.

The spelling of 2101949661 in words is "two billion, one hundred one million, nine hundred forty-nine thousand, six hundred sixty-one".