1656249881 has 16 divisors (see below), whose sum is σ = 1949111808. Its totient is φ = 1387497600.

The previous prime is 1656249869. The next prime is 1656249901. The reversal of 1656249881 is 1889426561.

It is a cyclic number.

It is not a de Polignac number, because 1656249881 - 2¹⁰ = 1656248857 is a prime.

It is a super-2 number, since 2×1656249881² = 5486327336625028322, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1656249821) 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, 77261 + ... + 96341.

It is an arithmetic number, because the mean of its divisors is an integer number (121819488).

Almost surely, 2^1656249881 is an apocalyptic number.

1656249881 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1656249881 is a deficient number, since it is larger than the sum of its proper divisors (292861927).

1656249881 is a wasteful number, since it uses less digits than its factorization.

1656249881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19712.

The product of its digits is 829440, while the sum is 50.

The square root of 1656249881 is about 40697.0500282269. The cubic root of 1656249881 is about 1183.1558444546.

The spelling of 1656249881 in words is "one billion, six hundred fifty-six million, two hundred forty-nine thousand, eight hundred eighty-one".