1621977023878 has 4 divisors (see below), whose sum is σ = 2432965535820. Its totient is φ = 810988511938.

The previous prime is 1621977023861. The next prime is 1621977023917. The reversal of 1621977023878 is 8783207791261.

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, 405494255968 + ... + 405494255971.

It is an arithmetic number, because the mean of its divisors is an integer number (608241383955).

Almost surely, 2^{1621977023878} is an apocalyptic number.

1621977023878 is a deficient number, since it is larger than the sum of its proper divisors (810988511942).

1621977023878 is an equidigital number, since it uses as much as digits as its factorization.

1621977023878 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 810988511941.

The product of its (nonzero) digits is 14224896, while the sum is 61.

The spelling of 1621977023878 in words is "one trillion, six hundred twenty-one billion, nine hundred seventy-seven million, twenty-three thousand, eight hundred seventy-eight".