61921915 has 16 divisors (see below), whose sum is σ = 81285120. Its totient is φ = 44909920.

The previous prime is 61921913. The next prime is 61921949. The reversal of 61921915 is 51912916.

It is a happy number.

It is not a de Polignac number, because 61921915 - 2¹ = 61921913 is a prime.

It is not an unprimeable number, because it can be changed into a prime (61921913) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 21702 + ... + 24388.

It is an arithmetic number, because the mean of its divisors is an integer number (5080320).

Almost surely, 2^61921915 is an apocalyptic number.

61921915 is a deficient number, since it is larger than the sum of its proper divisors (19363205).

61921915 is a wasteful number, since it uses less digits than its factorization.

61921915 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3122.

The product of its digits is 4860, while the sum is 34.

The square root of 61921915 is about 7869.0479093725. The cubic root of 61921915 is about 395.6229341934.

The spelling of 61921915 in words is "sixty-one million, nine hundred twenty-one thousand, nine hundred fifteen".