20951251 has 2 divisors, whose sum is σ = 20951252. Its totient is φ = 20951250.

The previous prime is 20951239. The next prime is 20951261. The reversal of 20951251 is 15215902.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20951251 - 2¹⁷ = 20820179 is a prime.

It is a super-3 number, since 3×20951251³ (a number of 23 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (20951201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10475625 + 10475626.

It is an arithmetic number, because the mean of its divisors is an integer number (10475626).

Almost surely, 2^20951251 is an apocalyptic number.

20951251 is a deficient number, since it is larger than the sum of its proper divisors (1).

20951251 is an equidigital number, since it uses as much as digits as its factorization.

20951251 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 900, while the sum is 25.

The square root of 20951251 is about 4577.2536525738. The cubic root of 20951251 is about 275.6787684313.

The spelling of 20951251 in words is "twenty million, nine hundred fifty-one thousand, two hundred fifty-one".