1995689721 has 8 divisors (see below), whose sum is σ = 2817444384. Its totient is φ = 1252197440.

The previous prime is 1995689713. The next prime is 1995689771. The reversal of 1995689721 is 1279865991.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1995689721 - 2³ = 1995689713 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1995689771) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19565535 + ... + 19565636.

It is an arithmetic number, because the mean of its divisors is an integer number (352180548).

Almost surely, 2^1995689721 is an apocalyptic number.

It is an amenable number.

1995689721 is a deficient number, since it is larger than the sum of its proper divisors (821754663).

1995689721 is a wasteful number, since it uses less digits than its factorization.

1995689721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39131191.

The product of its digits is 2449440, while the sum is 57.

The square root of 1995689721 is about 44673.1431734997. The cubic root of 1995689721 is about 1259.0152970345.

The spelling of 1995689721 in words is "one billion, nine hundred ninety-five million, six hundred eighty-nine thousand, seven hundred twenty-one".