20951573 has 2 divisors, whose sum is σ = 20951574. Its totient is φ = 20951572.

The previous prime is 20951537. The next prime is 20951591. The reversal of 20951573 is 37515902.

Together with previous prime (20951537) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13010449 + 7941124 = 3607^2 + 2818^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20951573 is a prime.

It is a super-2 number, since 2×20951573² = 877936822348658, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20951173) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10475786 + 10475787.

It is an arithmetic number, because the mean of its divisors is an integer number (10475787).

Almost surely, 2^20951573 is an apocalyptic number.

It is an amenable number.

20951573 is a deficient number, since it is larger than the sum of its proper divisors (1).

20951573 is an equidigital number, since it uses as much as digits as its factorization.

20951573 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9450, while the sum is 32.

The square root of 20951573 is about 4577.2888263687. The cubic root of 20951573 is about 275.6801807273.

The spelling of 20951573 in words is "twenty million, nine hundred fifty-one thousand, five hundred seventy-three".