61813409 has 4 divisors (see below), whose sum is σ = 70643904. Its totient is φ = 52982916.

The previous prime is 61813399. The next prime is 61813417. The reversal of 61813409 is 90431816.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 61813409 - 2⁴ = 61813393 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61813429) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4415237 + ... + 4415250.

It is an arithmetic number, because the mean of its divisors is an integer number (17660976).

Almost surely, 2^61813409 is an apocalyptic number.

It is an amenable number.

61813409 is a deficient number, since it is larger than the sum of its proper divisors (8830495).

61813409 is an equidigital number, since it uses as much as digits as its factorization.

61813409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8830494.

The product of its (nonzero) digits is 5184, while the sum is 32.

The square root of 61813409 is about 7862.1504055824. The cubic root of 61813409 is about 395.3917152433.

The spelling of 61813409 in words is "sixty-one million, eight hundred thirteen thousand, four hundred nine".