61809990 has 32 divisors (see below), whose sum is σ = 161830656. Its totient is φ = 14984160.

The previous prime is 61809967. The next prime is 61810003. The reversal of 61809990 is 9990816.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 93322 + ... + 93981.

It is an arithmetic number, because the mean of its divisors is an integer number (5057208).

Almost surely, 2^61809990 is an apocalyptic number.

61809990 is an abundant number, since it is smaller than the sum of its proper divisors (100020666).

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

61809990 is a wasteful number, since it uses less digits than its factorization.

61809990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 187324.

The product of its (nonzero) digits is 34992, while the sum is 42.

The square root of 61809990 is about 7861.9329684245. The cubic root of 61809990 is about 395.3844251897.

The spelling of 61809990 in words is "sixty-one million, eight hundred nine thousand, nine hundred ninety".