61653640007 has 4 divisors (see below), whose sum is σ = 63642467136. Its totient is φ = 59664812880.

The previous prime is 61653639977. The next prime is 61653640033. The reversal of 61653640007 is 70004635616.

It is a happy number.

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 61653640007 - 2¹⁰ = 61653638983 is a prime.

It is a super-2 number, since 2×61653640007² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61653640207) 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, 994413518 + ... + 994413579.

It is an arithmetic number, because the mean of its divisors is an integer number (15910616784).

Almost surely, 2^61653640007 is an apocalyptic number.

61653640007 is a deficient number, since it is larger than the sum of its proper divisors (1988827129).

61653640007 is a wasteful number, since it uses less digits than its factorization.

61653640007 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1988827128.

The product of its (nonzero) digits is 90720, while the sum is 38.

The spelling of 61653640007 in words is "sixty-one billion, six hundred fifty-three million, six hundred forty thousand, seven".