20071921 has 2 divisors, whose sum is σ = 20071922. Its totient is φ = 20071920.

The previous prime is 20071907. The next prime is 20071963. The reversal of 20071921 is 12917002.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20070400 + 1521 = 4480^2 + 39^2 .

It is a cyclic number.

It is not a de Polignac number, because 20071921 - 2⁹ = 20071409 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20071892 and 20071901.

It is not a weakly prime, because it can be changed into another prime (20071901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10035960 + 10035961.

It is an arithmetic number, because the mean of its divisors is an integer number (10035961).

Almost surely, 2^20071921 is an apocalyptic number.

It is an amenable number.

20071921 is a deficient number, since it is larger than the sum of its proper divisors (1).

20071921 is an equidigital number, since it uses as much as digits as its factorization.

20071921 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 252, while the sum is 22.

The square root of 20071921 is about 4480.1697512483. The cubic root of 20071921 is about 271.7667451336.

Adding to 20071921 its reverse (12917002), we get a palindrome (32988923).

The spelling of 20071921 in words is "twenty million, seventy-one thousand, nine hundred twenty-one".