20219951 has 2 divisors, whose sum is σ = 20219952. Its totient is φ = 20219950.

The previous prime is 20219939. The next prime is 20220007. The reversal of 20219951 is 15991202.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20219951 - 2⁶ = 20219887 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20219911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10109975 + 10109976.

It is an arithmetic number, because the mean of its divisors is an integer number (10109976).

Almost surely, 2^20219951 is an apocalyptic number.

20219951 is a deficient number, since it is larger than the sum of its proper divisors (1).

20219951 is an equidigital number, since it uses as much as digits as its factorization.

20219951 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1620, while the sum is 29.

The square root of 20219951 is about 4496.6599826983. The cubic root of 20219951 is about 272.4332008080.

The spelling of 20219951 in words is "twenty million, two hundred nineteen thousand, nine hundred fifty-one".