215901961 has 4 divisors (see below), whose sum is σ = 235529424. Its totient is φ = 196274500.

The previous prime is 215901911. The next prime is 215901967. The reversal of 215901961 is 169109512.

It is a happy number.

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 215901961 - 2¹⁵ = 215869193 is a prime.

It is a super-2 number, since 2×215901961² = 93227313527291042, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (215901967) 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, 9813715 + ... + 9813736.

It is an arithmetic number, because the mean of its divisors is an integer number (58882356).

Almost surely, 2^215901961 is an apocalyptic number.

It is an amenable number.

215901961 is a deficient number, since it is larger than the sum of its proper divisors (19627463).

215901961 is a wasteful number, since it uses less digits than its factorization.

215901961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19627462.

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

The square root of 215901961 is about 14693.6027236345. The cubic root of 215901961 is about 599.9092094106.

The spelling of 215901961 in words is "two hundred fifteen million, nine hundred one thousand, nine hundred sixty-one".