61157381 has 4 divisors (see below), whose sum is σ = 64754892. Its totient is φ = 57559872.

The previous prime is 61157357. The next prime is 61157401. The reversal of 61157381 is 18375116.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 17926756 + 43230625 = 4234^2 + 6575^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-61157381 is a prime.

It is a super-2 number, since 2×61157381² = 7480450501558322, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61157321) 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, 1798730 + ... + 1798763.

It is an arithmetic number, because the mean of its divisors is an integer number (16188723).

Almost surely, 2^61157381 is an apocalyptic number.

It is an amenable number.

61157381 is a deficient number, since it is larger than the sum of its proper divisors (3597511).

61157381 is a wasteful number, since it uses less digits than its factorization.

61157381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3597510.

The product of its digits is 5040, while the sum is 32.

The square root of 61157381 is about 7820.3184717759. The cubic root of 61157381 is about 393.9879684886.

The spelling of 61157381 in words is "sixty-one million, one hundred fifty-seven thousand, three hundred eighty-one".