1621047251 has 2 divisors, whose sum is σ = 1621047252. Its totient is φ = 1621047250.

The previous prime is 1621047151. The next prime is 1621047277. The reversal of 1621047251 is 1527401261.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1621047251 - 2¹⁴ = 1621030867 is a prime.

It is not a weakly prime, because it can be changed into another prime (1621047151) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 810523625 + 810523626.

It is an arithmetic number, because the mean of its divisors is an integer number (810523626).

Almost surely, 2^1621047251 is an apocalyptic number.

1621047251 is a deficient number, since it is larger than the sum of its proper divisors (1).

1621047251 is an equidigital number, since it uses as much as digits as its factorization.

1621047251 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3360, while the sum is 29.

The square root of 1621047251 is about 40262.2310733024. The cubic root of 1621047251 is about 1174.7133149382.

The spelling of 1621047251 in words is "one billion, six hundred twenty-one million, forty-seven thousand, two hundred fifty-one".