61691900 has 36 divisors (see below), whose sum is σ = 135772560. Its totient is φ = 24326400.

The previous prime is 61691881. The next prime is 61691909. The reversal of 61691900 is 919616.

It is a happy number.

It is a super-2 number, since 2×61691900² = 7611781051220000, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61691909) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2756 + ... + 11444.

It is an arithmetic number, because the mean of its divisors is an integer number (3771460).

Almost surely, 2^61691900 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 61691900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (67886280).

61691900 is an abundant number, since it is smaller than the sum of its proper divisors (74080660).

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

61691900 is a wasteful number, since it uses less digits than its factorization.

61691900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8774 (or 8767 counting only the distinct ones).

The product of its (nonzero) digits is 2916, while the sum is 32.

The square root of 61691900 is about 7854.4191382941. The cubic root of 61691900 is about 395.1324663870.

The spelling of 61691900 in words is "sixty-one million, six hundred ninety-one thousand, nine hundred".