1661897652 has 12 divisors (see below), whose sum is σ = 3877761216. Its totient is φ = 553965880.

The previous prime is 1661897651. The next prime is 1661897689. The reversal of 1661897652 is 2567981661.

It is a tau number, because it is divible by the number of its divisors (12).

It is a super-2 number, since 2×1661897652² = 5523807611446226208, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1661897595 and 1661897604.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661897651) 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, 69245724 + ... + 69245747.

It is an arithmetic number, because the mean of its divisors is an integer number (323146768).

Almost surely, 2^1661897652 is an apocalyptic number.

1661897652 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

1661897652 is an abundant number, since it is smaller than the sum of its proper divisors (2215863564).

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

1661897652 is a wasteful number, since it uses less digits than its factorization.

1661897652 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 138491478 (or 138491476 counting only the distinct ones).

The product of its digits is 1088640, while the sum is 51.

The square root of 1661897652 is about 40766.3789414758. The cubic root of 1661897652 is about 1184.4991627402.

The spelling of 1661897652 in words is "one billion, six hundred sixty-one million, eight hundred ninety-seven thousand, six hundred fifty-two".