61531145 has 24 divisors (see below), whose sum is σ = 81286296. Its totient is φ = 44448768.

The previous prime is 61531133. The next prime is 61531147. The reversal of 61531145 is 54113516.

It can be written as a sum of positive squares in 12 ways, for example, as 16801801 + 44729344 = 4099^2 + 6688^2 .

It is not a de Polignac number, because 61531145 - 2¹⁰ = 61530121 is a prime.

It is a super-2 number, since 2×61531145² = 7572163610022050, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (61531147) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 182417 + ... + 182753.

It is an arithmetic number, because the mean of its divisors is an integer number (3386929).

Almost surely, 2^61531145 is an apocalyptic number.

61531145 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

61531145 is a deficient number, since it is larger than the sum of its proper divisors (19755151).

61531145 is a wasteful number, since it uses less digits than its factorization.

61531145 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 461 (or 408 counting only the distinct ones).

The product of its digits is 1800, while the sum is 26.

The square root of 61531145 is about 7844.1790520105. The cubic root of 61531145 is about 394.7889595295.

The spelling of 61531145 in words is "sixty-one million, five hundred thirty-one thousand, one hundred forty-five".