1621977023865 has 64 divisors (see below), whose sum is σ = 2872199596032. Its totient is φ = 775002547200.

The previous prime is 1621977023861. The next prime is 1621977023917. The reversal of 1621977023865 is 5683207791261.

It is not a de Polignac number, because 1621977023865 - 2² = 1621977023861 is a prime.

It is a Smith number, since the sum of its digits (57) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (1621977023861) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 28286514 + ... + 28343796.

It is an arithmetic number, because the mean of its divisors is an integer number (44878118688).

Almost surely, 2^{1621977023865} is an apocalyptic number.

1621977023865 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1621977023865 is a deficient number, since it is larger than the sum of its proper divisors (1250222572167).

1621977023865 is a wasteful number, since it uses less digits than its factorization.

1621977023865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59790.

The product of its (nonzero) digits is 7620480, while the sum is 57.

The spelling of 1621977023865 in words is "one trillion, six hundred twenty-one billion, nine hundred seventy-seven million, twenty-three thousand, eight hundred sixty-five".