1620736542666 has 32 divisors (see below), whose sum is σ = 3617503030080. Its totient is φ = 537865573968.

The previous prime is 1620736542661. The next prime is 1620736542671. The reversal of 1620736542666 is 6662456370261.

It is an interprime number because it is at equal distance from previous prime (1620736542661) and next prime (1620736542671).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (1620736542661) 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 15 ways as a sum of consecutive naturals, for example, 66097081 + ... + 66121596.

It is an arithmetic number, because the mean of its divisors is an integer number (113046969690).

Almost surely, 2^{1620736542666} is an apocalyptic number.

1620736542666 is an abundant number, since it is smaller than the sum of its proper divisors (1996766487414).

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

1620736542666 is a wasteful number, since it uses less digits than its factorization.

1620736542666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 132218915 (or 132218909 counting only the distinct ones).

The product of its (nonzero) digits is 13063680, while the sum is 54.

The spelling of 1620736542666 in words is "one trillion, six hundred twenty billion, seven hundred thirty-six million, five hundred forty-two thousand, six hundred sixty-six".