20954581 has 2 divisors, whose sum is σ = 20954582. Its totient is φ = 20954580.

The previous prime is 20954579. The next prime is 20954627. The reversal of 20954581 is 18545902.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19722481 + 1232100 = 4441^2 + 1110^2 .

It is a cyclic number.

It is not a de Polignac number, because 20954581 - 2¹ = 20954579 is a prime.

It is a super-2 number, since 2×20954581² = 878188929771122, which contains 22 as substring.

Together with 20954579, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20954881) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10477290 + 10477291.

It is an arithmetic number, because the mean of its divisors is an integer number (10477291).

Almost surely, 2^20954581 is an apocalyptic number.

It is an amenable number.

20954581 is a deficient number, since it is larger than the sum of its proper divisors (1).

20954581 is an equidigital number, since it uses as much as digits as its factorization.

20954581 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 14400, while the sum is 34.

The square root of 20954581 is about 4577.6173933609. The cubic root of 20954581 is about 275.6933731545.

The spelling of 20954581 in words is "twenty million, nine hundred fifty-four thousand, five hundred eighty-one".