1621111653544 has 64 divisors (see below), whose sum is σ = 3388057200000. Its totient is φ = 722663866368.

The previous prime is 1621111653541. The next prime is 1621111653547. The reversal of 1621111653544 is 4453561111261.

It is an interprime number because it is at equal distance from previous prime (1621111653541) and next prime (1621111653547).

It is a junction number, because it is equal to n+sod(n) for n = 1621111653497 and 1621111653506.

It is not an unprimeable number, because it can be changed into a prime (1621111653541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 46621237 + ... + 46655995.

It is an arithmetic number, because the mean of its divisors is an integer number (52938393750).

Almost surely, 2^{1621111653544} is an apocalyptic number.

It is an amenable number.

1621111653544 is an abundant number, since it is smaller than the sum of its proper divisors (1766945546456).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1621111653544 is a wasteful number, since it uses less digits than its factorization.

1621111653544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52850 (or 52846 counting only the distinct ones).

The product of its digits is 86400, while the sum is 40.

The spelling of 1621111653544 in words is "one trillion, six hundred twenty-one billion, one hundred eleven million, six hundred fifty-three thousand, five hundred forty-four".