256621643026654 has 4 divisors (see below), whose sum is σ = 384932464539984. Its totient is φ = 128310821513326.

The previous prime is 256621643026649. The next prime is 256621643026673. The reversal of 256621643026654 is 456620346126652.

It is a semiprime because it is the product of two primes.

It is a super-3 number, since 3×256621643026654³ (a number of 44 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64155410756662 + ... + 64155410756665.

It is an arithmetic number, because the mean of its divisors is an integer number (96233116134996).

Almost surely, 2^{256621643026654} is an apocalyptic number.

256621643026654 is a deficient number, since it is larger than the sum of its proper divisors (128310821513330).

256621643026654 is a wasteful number, since it uses less digits than its factorization.

256621643026654 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128310821513329.

The product of its (nonzero) digits is 74649600, while the sum is 58.

The spelling of 256621643026654 in words is "two hundred fifty-six trillion, six hundred twenty-one billion, six hundred forty-three million, twenty-six thousand, six hundred fifty-four".