691990740 has 216 divisors, whose sum is σ = 2480298912. Its totient is φ = 155675520.

The previous prime is 691990727. The next prime is 691990769. The reversal of 691990740 is 47099196.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 590355 + ... + 591525.

Almost surely, 2^691990740 is an apocalyptic number.

691990740 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 691990740, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1240149456).

691990740 is an abundant number, since it is smaller than the sum of its proper divisors (1788308172).

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

691990740 is a wasteful number, since it uses less digits than its factorization.

691990740 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1267 (or 1255 counting only the distinct ones).

The product of its (nonzero) digits is 122472, while the sum is 45.

The square root of 691990740 is about 26305.7168691522. The cubic root of 691990740 is about 884.5045968145.

The spelling of 691990740 in words is "six hundred ninety-one million, nine hundred ninety thousand, seven hundred forty".