691144394 has 4 divisors (see below), whose sum is σ = 1036716594. Its totient is φ = 345572196.

The previous prime is 691144373. The next prime is 691144427. The reversal of 691144394 is 493441196.

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

It can be written as a sum of positive squares in only one way, i.e., 428283025 + 262861369 = 20695^2 + 16213^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 172786097 + ... + 172786100.

Almost surely, 2^691144394 is an apocalyptic number.

691144394 is a deficient number, since it is larger than the sum of its proper divisors (345572200).

691144394 is a wasteful number, since it uses less digits than its factorization.

691144394 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 345572199.

The product of its digits is 93312, while the sum is 41.

The square root of 691144394 is about 26289.6252160429. The cubic root of 691144394 is about 884.1438490546.

The spelling of 691144394 in words is "six hundred ninety-one million, one hundred forty-four thousand, three hundred ninety-four".