64121861 has 4 divisors (see below), whose sum is σ = 66909792. Its totient is φ = 61333932.

The previous prime is 64121843. The next prime is 64121867. The reversal of 64121861 is 16812146.

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 a de Polignac number, because none of the positive numbers 2^k-64121861 is a prime.

It is a super-2 number, since 2×64121861² = 8223226116206642, which 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 (64121867) 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, 1393931 + ... + 1393976.

It is an arithmetic number, because the mean of its divisors is an integer number (16727448).

Almost surely, 2^64121861 is an apocalyptic number.

It is an amenable number.

64121861 is a deficient number, since it is larger than the sum of its proper divisors (2787931).

64121861 is a wasteful number, since it uses less digits than its factorization.

64121861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2787930.

The product of its digits is 2304, while the sum is 29.

The square root of 64121861 is about 8007.6126904340. The cubic root of 64121861 is about 400.2537161196.

The spelling of 64121861 in words is "sixty-four million, one hundred twenty-one thousand, eight hundred sixty-one".