61911820 has 24 divisors (see below), whose sum is σ = 130196304. Its totient is φ = 24730176.

The previous prime is 61911809. The next prime is 61911833. The reversal of 61911820 is 2811916.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16434 + ... + 19846.

It is an arithmetic number, because the mean of its divisors is an integer number (5424846).

Almost surely, 2^61911820 is an apocalyptic number.

It is an amenable number.

61911820 is an abundant number, since it is smaller than the sum of its proper divisors (68284484).

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

61911820 is a wasteful number, since it uses less digits than its factorization.

61911820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4329 (or 4327 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 28.

The square root of 61911820 is about 7868.4064460347. The cubic root of 61911820 is about 395.6014338324.

The spelling of 61911820 in words is "sixty-one million, nine hundred eleven thousand, eight hundred twenty".