1945700721 has 6 divisors (see below), whose sum is σ = 2810456610. Its totient is φ = 1297133808.

The previous prime is 1945700707. The next prime is 1945700737. The reversal of 1945700721 is 1270075491.

It is a happy number.

1945700721 is a `hidden beast` number, since 19 + 4 + 570 + 0 + 72 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 1892250000 + 53450721 = 43500^2 + 7311^2 .

It is not a de Polignac number, because 1945700721 - 2⁹ = 1945700209 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1945700321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 108094476 + ... + 108094493.

It is an arithmetic number, because the mean of its divisors is an integer number (468409435).

Almost surely, 2^1945700721 is an apocalyptic number.

It is an amenable number.

1945700721 is a deficient number, since it is larger than the sum of its proper divisors (864755889).

1945700721 is a wasteful number, since it uses less digits than its factorization.

1945700721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 216188975 (or 216188972 counting only the distinct ones).

The product of its (nonzero) digits is 17640, while the sum is 36.

The square root of 1945700721 is about 44110.0977214968. The cubic root of 1945700721 is about 1248.4141427095.

The spelling of 1945700721 in words is "one billion, nine hundred forty-five million, seven hundred thousand, seven hundred twenty-one".