61644021151 has 4 divisors (see below), whose sum is σ = 63147533904. Its totient is φ = 60140508400.

The previous prime is 61644021133. The next prime is 61644021163. The reversal of 61644021151 is 15112044616.

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

It is a cyclic number.

It is not a de Polignac number, because 61644021151 - 2⁹ = 61644020639 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61644021121) 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, 751756315 + ... + 751756396.

It is an arithmetic number, because the mean of its divisors is an integer number (15786883476).

Almost surely, 2^61644021151 is an apocalyptic number.

61644021151 is a deficient number, since it is larger than the sum of its proper divisors (1503512753).

61644021151 is a wasteful number, since it uses less digits than its factorization.

61644021151 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1503512752.

The product of its (nonzero) digits is 5760, while the sum is 31.

Adding to 61644021151 its reverse (15112044616), we get a palindrome (76756065767).

The spelling of 61644021151 in words is "sixty-one billion, six hundred forty-four million, twenty-one thousand, one hundred fifty-one".