1020021661655 has 16 divisors (see below), whose sum is σ = 1296116165664. Its totient is φ = 767963781120.

The previous prime is 1020021661627. The next prime is 1020021661727. The reversal of 1020021661655 is 5561661200201.

It is not a de Polignac number, because 1020021661655 - 2³⁰ = 1018947919831 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 862799 + ... + 1668671.

It is an arithmetic number, because the mean of its divisors is an integer number (81007260354).

Almost surely, 2^{1020021661655} is an apocalyptic number.

1020021661655 is a deficient number, since it is larger than the sum of its proper divisors (276094504009).

1020021661655 is a wasteful number, since it uses less digits than its factorization.

1020021661655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 820786.

The product of its (nonzero) digits is 21600, while the sum is 35.

Adding to 1020021661655 its reverse (5561661200201), we get a palindrome (6581682861856).

The spelling of 1020021661655 in words is "one trillion, twenty billion, twenty-one million, six hundred sixty-one thousand, six hundred fifty-five".