21122078 has 4 divisors (see below), whose sum is σ = 31683120. Its totient is φ = 10561038.

The previous prime is 21122069. The next prime is 21122099. The reversal of 21122078 is 87022112.

It is a semiprime because it is the product of two primes.

It is a super-2 number, since 2×21122078² = 892284358076168, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5280518 + ... + 5280521.

It is an arithmetic number, because the mean of its divisors is an integer number (7920780).

Almost surely, 2^21122078 is an apocalyptic number.

21122078 is a deficient number, since it is larger than the sum of its proper divisors (10561042).

21122078 is a wasteful number, since it uses less digits than its factorization.

21122078 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10561041.

The product of its (nonzero) digits is 448, while the sum is 23.

The square root of 21122078 is about 4595.8761950253. The cubic root of 21122078 is about 276.4259944710.

The spelling of 21122078 in words is "twenty-one million, one hundred twenty-two thousand, seventy-eight".