61978687 has 2 divisors, whose sum is σ = 61978688. Its totient is φ = 61978686.

The previous prime is 61978649. The next prime is 61978717. The reversal of 61978687 is 78687916.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 61978687 - 2⁷ = 61978559 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61978607) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30989343 + 30989344.

It is an arithmetic number, because the mean of its divisors is an integer number (30989344).

Almost surely, 2^61978687 is an apocalyptic number.

61978687 is a deficient number, since it is larger than the sum of its proper divisors (1).

61978687 is an equidigital number, since it uses as much as digits as its factorization.

61978687 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1016064, while the sum is 52.

The square root of 61978687 is about 7872.6543808299. The cubic root of 61978687 is about 395.7438038650.

It can be divided in two parts, 6197 and 8687, that added together give a square (14884 = 122²).

The spelling of 61978687 in words is "sixty-one million, nine hundred seventy-eight thousand, six hundred eighty-seven".