2666401256542 has 4 divisors (see below), whose sum is σ = 3999601884816. Its totient is φ = 1333200628270.

The previous prime is 2666401256537. The next prime is 2666401256569. The reversal of 2666401256542 is 2456521046662.

It is a happy number.

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

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, 666600314134 + ... + 666600314137.

It is an arithmetic number, because the mean of its divisors is an integer number (999900471204).

Almost surely, 2^{2666401256542} is an apocalyptic number.

2666401256542 is a deficient number, since it is larger than the sum of its proper divisors (1333200628274).

2666401256542 is a wasteful number, since it uses less digits than its factorization.

2666401256542 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1333200628273.

The product of its (nonzero) digits is 4147200, while the sum is 49.

The spelling of 2666401256542 in words is "two trillion, six hundred sixty-six billion, four hundred one million, two hundred fifty-six thousand, five hundred forty-two".