251421019 has 2 divisors, whose sum is σ = 251421020. Its totient is φ = 251421018.

The previous prime is 251421013. The next prime is 251421089. The reversal of 251421019 is 910124152.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 251421019 - 2⁷ = 251420891 is a prime.

It is a super-2 number, since 2×251421019² = 126425057589996722, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 251420984 and 251421002.

It is not a weakly prime, because it can be changed into another prime (251421013) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 125710509 + 125710510.

It is an arithmetic number, because the mean of its divisors is an integer number (125710510).

Almost surely, 2^251421019 is an apocalyptic number.

251421019 is a deficient number, since it is larger than the sum of its proper divisors (1).

251421019 is an equidigital number, since it uses as much as digits as its factorization.

251421019 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 720, while the sum is 25.

The square root of 251421019 is about 15856.2611923492. The cubic root of 251421019 is about 631.1518517600.

The spelling of 251421019 in words is "two hundred fifty-one million, four hundred twenty-one thousand, nineteen".