1663642651 has 16 divisors (see below), whose sum is σ = 1830624768. Its totient is φ = 1499328000.

The previous prime is 1663642639. The next prime is 1663642697. The reversal of 1663642651 is 1562463661.

It is a cyclic number.

It is not a de Polignac number, because 1663642651 - 2⁹ = 1663642139 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1663643651) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1366395 + ... + 1367611.

It is an arithmetic number, because the mean of its divisors is an integer number (114414048).

Almost surely, 2^1663642651 is an apocalyptic number.

1663642651 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1663642651 is a deficient number, since it is larger than the sum of its proper divisors (166982117).

1663642651 is a wasteful number, since it uses less digits than its factorization.

1663642651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2202.

The product of its digits is 155520, while the sum is 40.

The square root of 1663642651 is about 40787.7757545076. The cubic root of 1663642651 is about 1184.9135939656.

The spelling of 1663642651 in words is "one billion, six hundred sixty-three million, six hundred forty-two thousand, six hundred fifty-one".