691142299218 has 450 divisors, whose sum is σ = 1911259232487. Its totient is φ = 186655084560.

The previous prime is 691142299201. The next prime is 691142299277. The reversal of 691142299218 is 812992241196.

It can be written as a sum of positive squares in only one way, i.e., 345571149609 + 345571149609 = 587853^2 + 587853^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=587853.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 224 ways as a sum of consecutive naturals, for example, 16073076705 + ... + 16073076747.

Almost surely, 2^691142299218 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 691142299218

691142299218 is an abundant number, since it is smaller than the sum of its proper divisors (1220116933269).

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

691142299218 is an frugal number, since it uses more digits than its factorization.

691142299218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 190 (or 86 counting only the distinct ones).

The product of its digits is 1119744, while the sum is 54.

It can be divided in two parts, 6911422 and 99218, that added together give a triangular number (7010640 = T₃₇₄₄).

The spelling of 691142299218 in words is "six hundred ninety-one billion, one hundred forty-two million, two hundred ninety-nine thousand, two hundred eighteen".