221251001 has 2 divisors, whose sum is σ = 221251002. Its totient is φ = 221251000.

The previous prime is 221250989. The next prime is 221251021. The reversal of 221251001 is 100152122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 212459776 + 8791225 = 14576^2 + 2965^2 .

It is a cyclic number.

It is not a de Polignac number, because 221251001 - 2¹⁸ = 220988857 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (221251021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110625500 + 110625501.

It is an arithmetic number, because the mean of its divisors is an integer number (110625501).

Almost surely, 2^221251001 is an apocalyptic number.

It is an amenable number.

221251001 is a deficient number, since it is larger than the sum of its proper divisors (1).

221251001 is an equidigital number, since it uses as much as digits as its factorization.

221251001 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 40, while the sum is 14.

The square root of 221251001 is about 14874.5084288524. The cubic root of 221251001 is about 604.8231625780.

The spelling of 221251001 in words is "two hundred twenty-one million, two hundred fifty-one thousand, one".