1663660251 has 12 divisors (see below), whose sum is σ = 2621525400. Its totient is φ = 1008278880.

The previous prime is 1663660247. The next prime is 1663660253. The reversal of 1663660251 is 1520663661.

1663660251 is a `hidden beast` number, since 16 + 6 + 36 + 602 + 5 + 1 = 666.

1663660251 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 1663660251 - 2² = 1663660247 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1663660253) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8402226 + ... + 8402423.

It is an arithmetic number, because the mean of its divisors is an integer number (218460450).

Almost surely, 2^1663660251 is an apocalyptic number.

1663660251 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1663660251 is a deficient number, since it is larger than the sum of its proper divisors (957865149).

1663660251 is a wasteful number, since it uses less digits than its factorization.

1663660251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16804666 (or 16804663 counting only the distinct ones).

The product of its (nonzero) digits is 38880, while the sum is 36.

The square root of 1663660251 is about 40787.9915048535. The cubic root of 1663660251 is about 1184.9177724282.

The spelling of 1663660251 in words is "one billion, six hundred sixty-three million, six hundred sixty thousand, two hundred fifty-one".