61138002121 has 9 divisors (see below), whose sum is σ = 71121730221. Its totient is φ = 52402518252.

The previous prime is 61138002113. The next prime is 61138002143. The reversal of 61138002121 is 12120083116.

The square root of 61138002121 is 247261.

It is a perfect power (a square), and thus also a powerful number.

61138002121 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 61138002121 - 2³ = 61138002113 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61138002151) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 1713166 + ... + 1748488.

It is an arithmetic number, because the mean of its divisors is an integer number (7902414469).

Almost surely, 2^61138002121 is an apocalyptic number.

61138002121 is the 247261-st square number.

61138002121 is the 123631-st centered octagonal number.

It is an amenable number.

61138002121 is a deficient number, since it is larger than the sum of its proper divisors (9983728100).

61138002121 is an frugal number, since it uses more digits than its factorization.

61138002121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 70660 (or 35330 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 25.

Multiplying 61138002121 by its sum of digits (25), we get a square (1528450053025 = 1236305²).

Multiplying 61138002121 by its product of nonzero digits (576), we get a square (35215489221696 = 5934264²).

Adding to 61138002121 its reverse (12120083116), we get a palindrome (73258085237).

The spelling of 61138002121 in words is "sixty-one billion, one hundred thirty-eight million, two thousand, one hundred twenty-one".