2156121551 has 8 divisors (see below), whose sum is σ = 2231890320. Its totient is φ = 2080447488.

The previous prime is 2156121491. The next prime is 2156121559. The reversal of 2156121551 is 1551216512.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2156121551 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (29).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2156121559) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24335 + ... + 70031.

It is an arithmetic number, because the mean of its divisors is an integer number (278986290).

Almost surely, 2^2156121551 is an apocalyptic number.

2156121551 is a deficient number, since it is larger than the sum of its proper divisors (75768769).

2156121551 is a wasteful number, since it uses less digits than its factorization.

2156121551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47353.

The product of its digits is 3000, while the sum is 29.

The square root of 2156121551 is about 46434.0559395795. The cubic root of 2156121551 is about 1291.8866592722.

The spelling of 2156121551 in words is "two billion, one hundred fifty-six million, one hundred twenty-one thousand, five hundred fifty-one".