61549987212 has 144 divisors (see below), whose sum is σ = 189577221120. Its totient is φ = 17211477024.

The previous prime is 61549987199. The next prime is 61549987249. The reversal of 61549987212 is 21278994516.

It is a happy number.

61549987212 is a `hidden beast` number, since 6 + 1 + 549 + 9 + 87 + 2 + 12 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 124993 + ... + 372455.

It is an arithmetic number, because the mean of its divisors is an integer number (1316508480).

Almost surely, 2^61549987212 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 61549987212, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (94788610560).

61549987212 is an abundant number, since it is smaller than the sum of its proper divisors (128027233908).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

61549987212 is a wasteful number, since it uses less digits than its factorization.

61549987212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 247537 (or 247522 counting only the distinct ones).

The product of its digits is 2177280, while the sum is 54.

The spelling of 61549987212 in words is "sixty-one billion, five hundred forty-nine million, nine hundred eighty-seven thousand, two hundred twelve".