1591661951 has 6 divisors (see below), whose sum is σ = 1749512856. Its totient is φ = 1446965300.

The previous prime is 1591661933. The next prime is 1591661989.

1591661951 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 1591661951 - 2⁶ = 1591661887 is a prime.

It is a super-2 number, since 2×1591661951² = 5066775532522252802, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1591661051) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 6576995 + ... + 6577236.

It is an arithmetic number, because the mean of its divisors is an integer number (291585476).

Almost surely, 2^1591661951 is an apocalyptic number.

1591661951 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1591661951 is a deficient number, since it is larger than the sum of its proper divisors (157850905).

1591661951 is a wasteful number, since it uses less digits than its factorization.

1591661951 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13154253 (or 13154242 counting only the distinct ones).

The product of its digits is 72900, while the sum is 44.

The square root of 1591661951 is about 39895.6382453020. The cubic root of 1591661951 is about 1167.5718388178.

The spelling of 1591661951 in words is "one billion, five hundred ninety-one million, six hundred sixty-one thousand, nine hundred fifty-one".