1621662157013 has 4 divisors (see below), whose sum is σ = 1717054048620. Its totient is φ = 1526270265408.

The previous prime is 1621662156977. The next prime is 1621662157019. The reversal of 1621662157013 is 3107512661261.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 1345467763249 + 276194393764 = 1159943^2 + 525542^2 .

It is a cyclic number.

It is not a de Polignac number, because 1621662157013 - 2¹⁴ = 1621662140629 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1621662157019) 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, 47695945778 + ... + 47695945811.

It is an arithmetic number, because the mean of its divisors is an integer number (429263512155).

Almost surely, 2^{1621662157013} is an apocalyptic number.

It is an amenable number.

1621662157013 is a deficient number, since it is larger than the sum of its proper divisors (95391891607).

1621662157013 is an equidigital number, since it uses as much as digits as its factorization.

1621662157013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95391891606.

The product of its (nonzero) digits is 90720, while the sum is 41.

The spelling of 1621662157013 in words is "one trillion, six hundred twenty-one billion, six hundred sixty-two million, one hundred fifty-seven thousand, thirteen".