1661697694 has 8 divisors (see below), whose sum is σ = 2493576648. Its totient is φ = 830505480.

The previous prime is 1661697689. The next prime is 1661697731. The reversal of 1661697694 is 4967961661.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×1661697694² = 5522478452489835272, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 165592 + ... + 175339.

It is an arithmetic number, because the mean of its divisors is an integer number (311697081).

Almost surely, 2^1661697694 is an apocalyptic number.

1661697694 is a deficient number, since it is larger than the sum of its proper divisors (831878954).

1661697694 is a wasteful number, since it uses less digits than its factorization.

1661697694 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 343370.

The product of its digits is 2939328, while the sum is 55.

The square root of 1661697694 is about 40763.9263810541. The cubic root of 1661697694 is about 1184.4516548841.

The spelling of 1661697694 in words is "one billion, six hundred sixty-one million, six hundred ninety-seven thousand, six hundred ninety-four".