2102391649 has 4 divisors (see below), whose sum is σ = 2226061764. Its totient is φ = 1978721536.

The previous prime is 2102391637. The next prime is 2102391679. The reversal of 2102391649 is 9461932012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1019652624 + 1082739025 = 31932^2 + 32905^2 .

It is a cyclic number.

It is not a de Polignac number, because 2102391649 - 2¹³ = 2102383457 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2102391679) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 61835032 + ... + 61835065.

It is an arithmetic number, because the mean of its divisors is an integer number (556515441).

Almost surely, 2^2102391649 is an apocalyptic number.

It is an amenable number.

2102391649 is a deficient number, since it is larger than the sum of its proper divisors (123670115).

2102391649 is a wasteful number, since it uses less digits than its factorization.

2102391649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123670114.

The product of its (nonzero) digits is 23328, while the sum is 37.

The square root of 2102391649 is about 45851.8445539544. The cubic root of 2102391649 is about 1281.0651227546.

The spelling of 2102391649 in words is "two billion, one hundred two million, three hundred ninety-one thousand, six hundred forty-nine".