61415781 has 32 divisors (see below), whose sum is σ = 100528128. Its totient is φ = 32551680.

The previous prime is 61415779. The next prime is 61415789. The reversal of 61415781 is 18751416.

It is a happy number.

It is not a de Polignac number, because 61415781 - 2¹ = 61415779 is a prime.

It is a super-2 number, since 2×61415781² = 7543796311679922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61415789) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 24136 + ... + 26558.

It is an arithmetic number, because the mean of its divisors is an integer number (3141504).

Almost surely, 2^61415781 is an apocalyptic number.

It is an amenable number.

61415781 is a deficient number, since it is larger than the sum of its proper divisors (39112347).

61415781 is a wasteful number, since it uses less digits than its factorization.

61415781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2521.

The product of its digits is 6720, while the sum is 33.

The square root of 61415781 is about 7836.8221237948. The cubic root of 61415781 is about 394.5420768233.

The spelling of 61415781 in words is "sixty-one million, four hundred fifteen thousand, seven hundred eighty-one".