1620957251 has 2 divisors, whose sum is σ = 1620957252. Its totient is φ = 1620957250.

The previous prime is 1620957167. The next prime is 1620957281. The reversal of 1620957251 is 1527590261.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1620957251 is a prime.

It is not a weakly prime, because it can be changed into another prime (1620957281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 810478625 + 810478626.

It is an arithmetic number, because the mean of its divisors is an integer number (810478626).

Almost surely, 2^1620957251 is an apocalyptic number.

1620957251 is a deficient number, since it is larger than the sum of its proper divisors (1).

1620957251 is an equidigital number, since it uses as much as digits as its factorization.

1620957251 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 37800, while the sum is 38.

The square root of 1620957251 is about 40261.1133850022. The cubic root of 1620957251 is about 1174.6915746394.

The spelling of 1620957251 in words is "one billion, six hundred twenty million, nine hundred fifty-seven thousand, two hundred fifty-one".