1602121661 has 4 divisors (see below), whose sum is σ = 1830996192. Its totient is φ = 1373247132.

The previous prime is 1602121657. The next prime is 1602121669. The reversal of 1602121661 is 1661212061.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1661212061 = 3691 ⋅450071.

It is a cyclic number.

It is not a de Polignac number, because 1602121661 - 2² = 1602121657 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 1602121661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1602121669) 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, 114437255 + ... + 114437268.

It is an arithmetic number, because the mean of its divisors is an integer number (457749048).

Almost surely, 2^1602121661 is an apocalyptic number.

It is an amenable number.

1602121661 is a deficient number, since it is larger than the sum of its proper divisors (228874531).

1602121661 is an equidigital number, since it uses as much as digits as its factorization.

1602121661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 228874530.

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 1602121661 is about 40026.5119764388. The cubic root of 1602121661 is about 1170.1238481410.

The spelling of 1602121661 in words is "one billion, six hundred two million, one hundred twenty-one thousand, six hundred sixty-one".