1625057281 has 4 divisors (see below), whose sum is σ = 1625148864. Its totient is φ = 1624965700.

The previous prime is 1625057267. The next prime is 1625057297. The reversal of 1625057281 is 1827505261.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1625057281 is a prime.

It is a super-2 number, since 2×1625057281² = 5281622333062225922, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1625057281.

It is not an unprimeable number, because it can be changed into a prime (1625057261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9685 + ... + 57826.

It is an arithmetic number, because the mean of its divisors is an integer number (406287216).

Almost surely, 2^1625057281 is an apocalyptic number.

It is an amenable number.

1625057281 is a deficient number, since it is larger than the sum of its proper divisors (91583).

1625057281 is an equidigital number, since it uses as much as digits as its factorization.

1625057281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91582.

The product of its (nonzero) digits is 33600, while the sum is 37.

The square root of 1625057281 is about 40311.9992185950. Note that the first 3 decimals coincide. The cubic root of 1625057281 is about 1175.6811577291.

The spelling of 1625057281 in words is "one billion, six hundred twenty-five million, fifty-seven thousand, two hundred eighty-one".