1995690210721 has 3 divisors (see below), whose sum is σ = 1995691623411. Its totient is φ = 1995688798032.

The previous prime is 1995690210677. The next prime is 1995690210737. The reversal of 1995690210721 is 1270120965991.

The square root of 1995690210721 is 1412689.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 1948148769121 + 47541441600 = 1395761^2 + 218040^2 .

It is not a de Polignac number, because 1995690210721 - 2¹³ = 1995690202529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1995690210781) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 706345 + ... + 2119033.

It is an arithmetic number, because the mean of its divisors is an integer number (665230541137).

Almost surely, 2^{1995690210721} is an apocalyptic number.

1995690210721 is the 1412689-th square number.

1995690210721 is the 706345-th centered octagonal number.

It is an amenable number.

1995690210721 is a deficient number, since it is larger than the sum of its proper divisors (1412690).

1995690210721 is an frugal number, since it uses more digits than its factorization.

1995690210721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2825378 (or 1412689 counting only the distinct ones).

The product of its (nonzero) digits is 612360, while the sum is 52.

The spelling of 1995690210721 in words is "one trillion, nine hundred ninety-five billion, six hundred ninety million, two hundred ten thousand, seven hundred twenty-one".