61381987 has 4 divisors (see below), whose sum is σ = 61721296. Its totient is φ = 61042680.

The previous prime is 61381937. The next prime is 61381993. The reversal of 61381987 is 78918316.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-61381987 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61381907) 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, 169383 + ... + 169744.

It is an arithmetic number, because the mean of its divisors is an integer number (15430324).

Almost surely, 2^61381987 is an apocalyptic number.

61381987 is a deficient number, since it is larger than the sum of its proper divisors (339309).

61381987 is a wasteful number, since it uses less digits than its factorization.

61381987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 339308.

The product of its digits is 72576, while the sum is 43.

The square root of 61381987 is about 7834.6657235647. The cubic root of 61381987 is about 394.4696980253.

The spelling of 61381987 in words is "sixty-one million, three hundred eighty-one thousand, nine hundred eighty-seven".