245661421 has 2 divisors, whose sum is σ = 245661422. Its totient is φ = 245661420.

The previous prime is 245661397. The next prime is 245661439. The reversal of 245661421 is 124166542.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 222755625 + 22905796 = 14925^2 + 4786^2 .

It is a cyclic number.

It is not a de Polignac number, because 245661421 - 2⁷ = 245661293 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (245661121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 122830710 + 122830711.

It is an arithmetic number, because the mean of its divisors is an integer number (122830711).

Almost surely, 2^245661421 is an apocalyptic number.

It is an amenable number.

245661421 is a deficient number, since it is larger than the sum of its proper divisors (1).

245661421 is an equidigital number, since it uses as much as digits as its factorization.

245661421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11520, while the sum is 31.

The square root of 245661421 is about 15673.5899206276. The cubic root of 245661421 is about 626.2950605755.

The spelling of 245661421 in words is "two hundred forty-five million, six hundred sixty-one thousand, four hundred twenty-one".