101920561 has 4 divisors (see below), whose sum is σ = 101990500. Its totient is φ = 101850624.

The previous prime is 101920549. The next prime is 101920573. The reversal of 101920561 is 165029101.

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

It is an interprime number because it is at equal distance from previous prime (101920549) and next prime (101920573).

It can be written as a sum of positive squares in 2 ways, for example, as 13184161 + 88736400 = 3631^2 + 9420^2 .

It is a cyclic number.

It is not a de Polignac number, because 101920561 - 2⁷ = 101920433 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (101920501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 32736 + ... + 35713.

It is an arithmetic number, because the mean of its divisors is an integer number (25497625).

Almost surely, 2^101920561 is an apocalyptic number.

It is an amenable number.

101920561 is a deficient number, since it is larger than the sum of its proper divisors (69939).

101920561 is an equidigital number, since it uses as much as digits as its factorization.

101920561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69938.

The product of its (nonzero) digits is 540, while the sum is 25.

The square root of 101920561 is about 10095.5713557976. The cubic root of 101920561 is about 467.1115455415. Note that the first 3 decimals are identical.

Adding to 101920561 its reverse (165029101), we get a palindrome (266949662).

The spelling of 101920561 in words is "one hundred one million, nine hundred twenty thousand, five hundred sixty-one".