20150021 has 2 divisors, whose sum is σ = 20150022. Its totient is φ = 20150020.

The previous prime is 20149973. The next prime is 20150033. The reversal of 20150021 is 12005102.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17222500 + 2927521 = 4150^2 + 1711^2 .

It is a cyclic number.

It is not a de Polignac number, because 20150021 - 2⁶ = 20149957 is a prime.

It is a super-3 number, since 3×20150021³ (a number of 23 digits) contains 333 as substring.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 20149984 and 20150011.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20150071) 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 as a sum of consecutive naturals, namely, 10075010 + 10075011.

It is an arithmetic number, because the mean of its divisors is an integer number (10075011).

Almost surely, 2^20150021 is an apocalyptic number.

It is an amenable number.

20150021 is a deficient number, since it is larger than the sum of its proper divisors (1).

20150021 is an equidigital number, since it uses as much as digits as its factorization.

20150021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 20, while the sum is 11.

The square root of 20150021 is about 4488.8774766082. The cubic root of 20150021 is about 272.1187711188.

Adding to 20150021 its reverse (12005102), we get a palindrome (32155123).

The spelling of 20150021 in words is "twenty million, one hundred fifty thousand, twenty-one".