4256687921 has 4 divisors (see below), whose sum is σ = 4316641344. Its totient is φ = 4196734500.

The previous prime is 4256687917. The next prime is 4256687969. The reversal of 4256687921 is 1297866524.

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 4256687921 - 2² = 4256687917 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 4256687921.

It is not an unprimeable number, because it can be changed into a prime (4256684921) 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, 29976605 + ... + 29976746.

It is an arithmetic number, because the mean of its divisors is an integer number (1079160336).

Almost surely, 2^4256687921 is an apocalyptic number.

It is an amenable number.

4256687921 is a deficient number, since it is larger than the sum of its proper divisors (59953423).

4256687921 is an equidigital number, since it uses as much as digits as its factorization.

4256687921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 59953422.

The product of its digits is 1451520, while the sum is 50.

The square root of 4256687921 is about 65243.2979010105. The cubic root of 4256687921 is about 1620.6551129069.

The spelling of 4256687921 in words is "four billion, two hundred fifty-six million, six hundred eighty-seven thousand, nine hundred twenty-one".