1021661236351 has 4 divisors (see below), whose sum is σ = 1167612841552. Its totient is φ = 875709631152.

The previous prime is 1021661236333. The next prime is 1021661236363. The reversal of 1021661236351 is 1536321661201.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1021661236351 - 2¹¹ = 1021661234303 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1021661236351.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1021661236301) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 72975802590 + ... + 72975802603.

It is an arithmetic number, because the mean of its divisors is an integer number (291903210388).

Almost surely, 2^{1021661236351} is an apocalyptic number.

1021661236351 is a deficient number, since it is larger than the sum of its proper divisors (145951605201).

1021661236351 is an equidigital number, since it uses as much as digits as its factorization.

1021661236351 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 145951605200.

The product of its (nonzero) digits is 38880, while the sum is 37.

Adding to 1021661236351 its reverse (1536321661201), we get a palindrome (2557982897552).

The spelling of 1021661236351 in words is "one trillion, twenty-one billion, six hundred sixty-one million, two hundred thirty-six thousand, three hundred fifty-one".