2151776681 has 4 divisors (see below), whose sum is σ = 2221188864. Its totient is φ = 2082364500.

The previous prime is 2151776659. The next prime is 2151776747. The reversal of 2151776681 is 1866771512.

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.

It is a cyclic number.

It is not a de Polignac number, because 2151776681 - 2⁶ = 2151776617 is a prime.

It is a super-2 number, since 2×2151776681² = 9260285769790751522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2151776651) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 34706045 + ... + 34706106.

It is an arithmetic number, because the mean of its divisors is an integer number (555297216).

Almost surely, 2^2151776681 is an apocalyptic number.

It is an amenable number.

2151776681 is a deficient number, since it is larger than the sum of its proper divisors (69412183).

2151776681 is an equidigital number, since it uses as much as digits as its factorization.

2151776681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69412182.

The product of its digits is 141120, while the sum is 44.

The square root of 2151776681 is about 46387.2469650873. The cubic root of 2151776681 is about 1291.0183015832.

The spelling of 2151776681 in words is "two billion, one hundred fifty-one million, seven hundred seventy-six thousand, six hundred eighty-one".