61201661 has 4 divisors (see below), whose sum is σ = 62503872. Its totient is φ = 59899452.

The previous prime is 61201631. The next prime is 61201669. The reversal of 61201661 is 16610216.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 61201661 - 2¹⁴ = 61185277 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61201669) 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, 651035 + ... + 651128.

It is an arithmetic number, because the mean of its divisors is an integer number (15625968).

Almost surely, 2^61201661 is an apocalyptic number.

It is an amenable number.

61201661 is a deficient number, since it is larger than the sum of its proper divisors (1302211).

61201661 is a wasteful number, since it uses less digits than its factorization.

61201661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1302210.

The product of its (nonzero) digits is 432, while the sum is 23.

The square root of 61201661 is about 7823.1490462601. The cubic root of 61201661 is about 394.0830323943.

Adding to 61201661 its reverse (16610216), we get a palindrome (77811877).

The spelling of 61201661 in words is "sixty-one million, two hundred one thousand, six hundred sixty-one".